Lucy Letby (born 4 January 1990) is a British former neonatal nurse who was convicted of murdering seven infants and attempting to murder seven others at the Countess of Chester Hospital between June 2015 and June 2016. She came under investigation after an unusual cluster of deaths and collapses in the hospital's neonatal unit, three years after she began working there.
Charged in November 2020 with seven counts of murder and fifteen counts of attempted murder relating to seventeen babies, Letby was prosecuted on the basis of her presence during many of the incidents, two abnormal blood test results and skin discolouration interpreted as signs of insulin poisoning and air embolism, alleged inconsistencies in medical records, her removal of nursing handover sheets from the hospital, and handwritten notes that the prosecution characterised as a confession. In August 2023, she was found guilty on seven counts each of murder and attempted murder, acquitted on two counts of attempted murder, and the jury was unable to reach verdicts on six further counts. She received a whole life order. One of the unresolved attempted murder charges was retried in July 2024, resulting in a further conviction.
Senior management at the Countess of Chester Hospital were criticised for failing to act on clinicians' concerns, prompting the British government to commission an independent statutory inquiry, which began hearings in September 2024. Cheshire Police examined additional cases, but the Crown Prosecution Service declined to bring further charges.
Following the lifting of reporting restrictions, several medical and statistical experts have challenged the prosecution's interpretation of the clinical and numerical evidence, arguing that the infants' deteriorations were consistent with natural causes. Two applications for permission to appeal have been refused by the Court of Appeal, and the Criminal Cases Review Commission is considering an application to refer the case back to the court.
Early life and education
Lucy Letby was born on 4 January 1990 in Hereford,[1] the only child of a furniture salesman[2] and an accounts clerk.[3] She attended St. James' Church of England primary school,[1]Aylestone School and Hereford Sixth Form College.[3] According to a friend interviewed by the BBC, she had long expressed an interest in neonatal nursing.[4][5]:18:40[6]
Letby studied child nursing at the University of Chester, completing clinical placements at Liverpool Women's Hospital and the Countess of Chester Hospital.[3][7] During her final year she failed an assessed placement but passed a subsequent retrieval placement after requesting a different assessor.[8] One of her assessors later told the 2024 statutory inquiry that she had considered Letby inexperienced and lacking confidence in some clinical areas.[9][10] Letby graduated with a Bachelor of Science in Nursing in 2011 with a speciality in child nursing in September 2011[3] and completed a further placement at Liverpool Women's Hospital the following year.[11]
Career
Letby began working as a registered nurse in the neonatal unit at the Countess of Chester Hospital on 2 January 2012.[11][12] She lived in rented accommodation before purchasing a house near the hospital in 2016.[11] In a 2013 staff profile she described her role as caring for babies requiring different levels of support, and she took part in a fundraising campaign for a new neonatal unit.[13][14] Colleagues later recalled that she sometimes described non‑intensive care work as boring.[15]
She completed a neonatal specialisation course in March 2014 and undertook further training at Liverpool Women's Hospital in early 2015,[16] and qualified to work with infants in intensive care. Her time there came under investigation after her conviction.[7][12]
In July 2013, Letby and a senior colleague set a morphine infusion rate incorrectly, leading the deputy ward manager to suspend her from administering controlled drugs and require additional training. The suspension was lifted a week later after she raised the matter with the unit manager. [17][18][19][16] In April 2016, she administered antibiotics that had not been prescribed, which she described as a minor error, and she was subsequently moved from night shifts to day shifts.[18][20][21]
In June 2016, lead neonatologist Stephen Brearey asked hospital management to remove Letby from clinical duties pending an investigation.[20] She was transferred to the patient experience team the following month and later to the risk and patient safety office, where she remained until her arrest in 2018.[22]
Initial investigations
Concerns about an increase in infant collapses[a] and deaths in the neonatal unit at the Countess of Chester Hospital first arose in June 2015, when four collapses occurred, three of them fatal.[20] The unit normally recorded two or three deaths a year.[5]:23:40 The unit manager, Eirian Powell, and lead neonatologist Brearey carried out an informal review and reported the incidents to the trust's serious‑incident committee, which classified the deaths as medication errors. Brearey noted that Letby had been on duty for each incident[20] but regarded this as an unsurprising coincidence, given staffing levels. He later told the statutory inquiry that no concerns had been raised about her practice at the time.[4] Subsequent reporting in 2023 indicated that he had developed suspicions earlier and believed the trust failed to act on them.[24][20]
A Care Quality Commission inspection in February 2016 heard concerns about difficulties raising issues with managers but was not informed of an elevated mortality rate. Its report highlighted staffing and skill‑mix problems but described a generally positive organisational culture.[22] In May 2016, the trust's executive team concluded that the rise in deaths was coincidental.[25] National MBRRACE‑UK data later showed that the unit's neonatal death rate between June 2015 and June 2016 was at least 10 per cent higher than expected, with deaths in 2015 double those of the previous year.[26][27]
On 24 June 2016, following two further deaths, Brearey asked the duty executive to remove Letby from clinical duties, but was told she was safe to work.[25][28] The trust's executive directors discussed involving the police but instead commissioned a review by the Royal College of Paediatrics and Child Health (RCPCH).[20] Letby was taken off the unit on 30 June, and the hospital subsequently reduced cot capacity and raised the gestational‑age threshold for admissions.[29][30]
The RCPCH review began in September 2016.[20] Its October report found no definitive explanation for the increased mortality rate but identified inadequate staffing and senior cover. It described concerns about Letby as subjective and unsupported by evidence.[4] The trust's medical director asked consultant neonatologist Jane Hawdon to undertake detailed case reviews recommended by the RCPCH. Hawdon instead conducted a brief review of medical notes relating to 17 deaths and collapses,[31][32] concluding that most could be explained and might have been preventable with different care, while four warranted further local forensic review.[33][20][22][34] Minutes of a subsequent board meeting recorded the medical director stating that the RCPCH and Hawdon reviews attributed the deaths to leadership and intervention issues;[28] the board chair later said he had been misled about the depth of Hawdon's review.[31]
Letby lodged a formal grievance in September 2016 regarding her removal from clinical duties.[28] The trust upheld the grievance in January 2017, concluding that her transfer had been orchestrated by consultants without firm evidence.[22] The chief executive apologised to Letby and her parents in December 2016 and instructed consultants to apologise to her in writing.[20][35][36]
In March 2017, four consultants, including Brearey and Ravi Jayaram, again asked management to involve the police after receiving advice from the regional neonatal lead.[22][37] They met Cheshire Constabulary on 27 April, shortly before Letby was due to return to clinical work. The trust publicly announced police involvement in May 2017,[36] stating that it sought assurances to rule out unnatural causes of death.[38][22][39] The resulting investigation, Operation Hummingbird, lasted a year.[40][41] Senior Investigating Officer Paul Hughes later said the inquiry initially considered a range of natural and clinical explanations alongside the possibility of inflicted harm.[42]:4:32
After reading about the investigation, retired paediatrician and expert witness Dewi Evans contacted the National Crime Agency offering assistance.[43][44] He was instructed to review clinical records for 61 cases of sudden collapse or death. Evans produced multiple reports for Cheshire Police, and his conclusions were peer‑reviewed by consultant neonatologist Sandie Bohin.[44][45] He also advised on the appointment of further specialist experts. The police ultimately narrowed the investigation to 22 cases, which formed the basis of the charges at Letby's trial.[44]
2023 trial
Police arrested Letby on 3 July 2018 on suspicion of eight counts of murder and six counts of attempted murder.[41] Following her arrest, detectives began reviewing her entire nursing career, including her time at Liverpool Women's Hospital.[34] She was bailed on 6 July, rearrested in June 2019, and bailed again shortly afterwards.[46][47][48] Letby was arrested for a third time in November 2020 and was remanded in custody.[49][50][51] She denied all allegations, attributing the collapses to issues such as staffing levels and hygiene.[52]
Letby's trial opened at Manchester Crown Court on 10 October 2022 before Mr Justice Goss.[53][54] She pleaded not guilty to seven counts of murder and 15 counts of attempted murder.[55] Her parents and the families of the infants attended the proceedings.[56][57]
The infants were anonymised as Baby A to Baby Q.[58][44] Reporting restrictions also protected the identities of nine colleagues who gave evidence.[59] Two years before the trial, Mrs Justice Steyn had ordered that the surviving infants could not be identified until adulthood. Several adult witnesses were also granted anonymity, which the court considered necessary to secure their testimony.[59]
Evidence
At trial, the prosecution presented evidence from parents, clinicians and expert witnesses. The mother of Baby E testified that she had heard her son cry and found blood around his mouth while Letby was present; Letby attributed the blood to a nasogastric tube.[60] Baby E died later that day.[60] Letby subsequently sent a sympathy card to the family,[5]:13:55 photographs of which were later found on her phone.[42][61] The court also heard that she had been advised more than once not to enter a room where bereaved parents were grieving.[62]
Prosecutors cited text messages sent by Letby to colleagues, which they said showed inappropriate interest in clinical events.[63][64] Messages included offers to take additional intensive‑care shifts shortly after deaths or collapses, expressions of frustration when not allocated to intensive‑care rooms, and comments about fate following a series of deaths.[65][66][67] The court also heard that Letby had searched for the families of several infants on Facebook,[42] sometimes on anniversaries or significant dates.[68][69] She told the jury this reflected general curiosity and frequent phone use.[68][4]
Consultants testified that they believed suspicious incidents began after Letby qualified to work in intensive care in 2015[16] and that the pattern of collapses shifted after she was moved from night to day shifts in 2016.[20][64] One consultant said he had found Letby standing over a deteriorating infant in February 2016 and believed she had not intervened promptly; the infant survived.[5]:22:55 Other clinicians described a cluster of near‑fatal collapses between March and June 2016, including the deaths of two triplets on consecutive days.[5]:26:25
The prosecution alleged that two infants, Baby F and Baby L, had been deliberately poisoned with insulin, citing blood test results identified during the police investigation.[25][70] Their lead expert witness described this as key evidence, though their interpretation has since been questioned by some specialists.[71] The prosecution also argued that Baby M, the twin of Baby L, collapsed after air was injected into his bloodstream.[70] Letby had volunteered for the shift on which Baby L collapsed, despite not being scheduled for night duty.[72]
Several consultants told the court they had previously raised concerns about Letby but were discouraged by hospital managers. One doctor recalled Letby making a remark shortly before an infant's death that he interpreted as inappropriate.[73][74][75][76] The prosecution also presented a shift‑pattern chart showing Letby on duty for 25 incidents, supported by swipe‑card data.[77][78] The chart has since been criticised by statisticians as misleading.[77][4] After Letby was removed from clinical duties, the unit's admission criteria were tightened to stop receiving the sickest babies, and more consultants were hired,[20][79] the unexpected deaths ceased.[77] The prosecution further alleged that Letby altered times on patient records; she denied this, saying any discrepancies were errors.[80]
Handwritten notes
Police searches of Letby's home, her parents' home,[81] and her handbag recovered several handwritten notes containing distressed and contradictory statements.[42][68][42][82] The prosecution characterised some of the phrases as incriminating, while the defence said they reflected emotional turmoil during employment disputes and the stress of being removed from clinical duties.[83] Letby denied that the notes were a confession.[84] Some criminology experts have since questioned the prosecution's interpretation, and later reporting indicated that the notes had been written on her GP's advice as a coping mechanism.[68][85][86][87]
Medical records
Police searches of Letby's home recovered sensitive medical documents, including nursing handover sheets, resuscitation records and blood‑gas printouts.[5]:44:00[87][42] A total of 257 sheets were found, 21 of which related to infants she was later accused of harming.[87][42] Letby told the court that she often forgot to remove paperwork from her pockets after shifts and described herself as someone who "collect[ed] paper". She also said she had been unable to destroy the documents, although a paper shredder was found in her home.[42]
Letby's testimony
Letby gave evidence in May 2023. Under questioning by her defence barrister, she became tearful and said she had been made to feel incompetent but had "meant no harm."[88] She told the court that the allegations had severely affected her mental health and left her feeling isolated from colleagues.[5]:51:00 Reporting from the trial noted that she sometimes contradicted herself, became confused about aspects of her account and grew increasingly frustrated during cross‑examination, which observers contrasted with her usual calm presentation.[89]
Defence arguments
Letby's defence argued that she was a dedicated nurse working within a system that had failed, and that the prosecution's case relied on assumptions of deliberate harm combined with her presence during certain incidents. They contended that shortcomings in staffing and care on the neonatal unit were extensive and could not reasonably be attributed to a single individual.[90] The defence also suggested that "extraordinary bleeding" in one infant might have been caused by medical equipment rather than deliberate injury.[91][92]
Counsel for the defence maintained that the prosecution had not presented sufficient evidence to support its theories of how the infants were harmed. They argued that the evidence for air embolism was too weak to sustain the allegation and noted that the term did not appear in Letby's internet search history. No independent medical experts were called by the defence.[4]
The only defence witness other than Letby was a plumber who testified that the unit had recurring plumbing problems, including sewage backing up into sinks, which he said required frequent call‑outs. The defence suggested that such hygiene issues could have contributed to the unit's elevated mortality rate. In later reporting, Dewi Evans acknowledged that pseudomonas had been detected in the unit's water supply, leading to several cases of pneumonia.[93]
The defence submitted that there was no case to answer on the air‑embolism allegations, arguing that the prosecution's experts lacked sufficient clinical experience, that the research basis for air embolism was inconsistent, and that expert descriptions of the condition varied.[44] Goss ruled that there was "a sufficient body of accepted medical opinion" to allow the allegation to be considered by the jury.[44]
Verdicts and sentencing
Final verdicts were delivered on 18 August 2023. Letby was found guilty of seven counts of murder and seven counts of attempted murder relating to six further infants. Eleven of the convictions were reached by a 10–1 majority, while the verdicts concerning Children F, L and O were unanimous. She was acquitted on two counts of attempted murder, and the jury was unable to reach verdicts on six additional attempted murder charges. The prosecution requested 28 days to consider whether to seek a retrial on those counts.[94]
The jury acquitted Letby of the attempted murder on counts 9 (Baby G) and 10 (Baby H), and was unable to reach verdicts on counts 11 (Baby H), 13 (Baby J), 14, (Baby K), 18 and 19 (Baby N), and 22 (Baby Q).[44]
On 21 August 2023, Letby was sentenced to life imprisonment with a whole life order, the most severe penalty available under English law. She became the fourth woman in the UK to receive such a sentence.[99] In his remarks, Goss described her actions as "a cruel, calculated and cynical campaign of child murder involving the smallest and most vulnerable of children", adding that "there was a deep malevolence bordering on sadism [...] you [Letby] have no remorse [...] there are no mitigating factors [...] the offences are of sufficient severity to require a whole life order."[100][101]
Letby chose not to attend the sentencing hearing and therefore did not hear the victim impact statements or the sentence being passed.[102][103][101] In response, the Secretary of State for Justice, Alex Chalk, said the government would "look at options to change the law at the earliest opportunity" to require defendants to attend their sentencing.[104] On 30 August 2023, Prime Minister Rishi Sunak announced plans to introduce legislation enabling courts to compel attendance, including by force, or impose additional prison time for refusal.[105] A clause to this effect was later proposed during parliamentary consideration of the criminal justice bill in 2024.[106]
No motive was established in court, and none is required for a conviction.[108][109][110] Prosecutors suggested several possible explanations, including boredom, thrill‑seeking and "playing God". They also alleged that Letby had formed an inappropriate emotional attachment to a married doctor involved in some of the cases, citing frequent text exchanges and a note found in her home containing phrases such as "I trusted you with everything and loved you", "you were my best friend" and "please help me".[111] Letby denied all suggestions of a motive and rejected claims that she had a relationship with, or feelings for, the doctor.[68][112]
Commentators drew comparisons with the Beverley Allitt case. The former detective who led the Allitt investigation suggested that Letby might have imitated Allitt's methods.[113]:17:30 Criminal psychologists Dominic Wilmott and David Holmes proposed that Letby could have been motivated by factitious disorder imposed on another, a theory also raised in relation to Allitt.[113]:18:00[114]31:15
David Wilson, an emeritus professor of criminology, argued in an August 2023 opinion piece that Letby was driven by a "hero complex".[115] Later that month, he said in a television interview that some healthcare killers enter the profession in order to target particularly vulnerable patients.[116]
Post-conviction
Disciplinary action
On 13 March 2020, while on bail, Letby was placed on an interim suspension by the Nursing and Midwifery Council.[117][118] On 18 August 2023, Andrea Sutcliffe, the Council's Chief Executive and Registrar, said that Letby "remains suspended from our register",[119] and that the NMC would begin regulatory action to remove her from the profession. Letby was struck off on 12 December 2023 after informing the Council that she did not accept guilt but would not contest her removal.[120]
Appeal
In January 2024, Letby applied to the Court of Appeal for permission to challenge her convictions, but this was refused by a single judge.[121] She renewed her application,[122] and at a three‑day hearing in April 2024 her legal team advanced four grounds of appeal relating to the trial judge's rulings. In May 2024, a panel comprising Dame Victoria Sharp, Lord Justice Holroyde and Mrs Justice Lambert refused permission to appeal.[123][124]
As part of the appeal, Letby's counsel, Ben Myers, again challenged the admission of evidence from paediatrician Evans, arguing that it should have been excluded on the basis that Evans had been "dogmatic and biased".[125][126] The appeal judges rejected this, finding that Evans did not lack impartiality, was suitably qualified to give expert evidence, and that it was for the jury to assess its weight.[126]
A second ground of appeal concerned the medical evidence relating to alleged fatal air injections, which the defence described as "very weak". A third ground argued that the trial judge had erred in directing the jury that they could convict even if they were uncertain about the precise method used in each case.[125] The final ground alleged that the judge had failed to investigate a question of juror impartiality.[125] All four grounds were dismissed, with the Court concluding in its written judgment that the trial had been "thoughtful, fair, comprehensive and correct" and that none of the challenges raised by the defence were "arguable".[125]
Retrial
At a hearing on 25 September 2023, the Crown Prosecution Service confirmed that there would be a retrial on one of the six attempted‑murder counts on which the original jury had been unable to reach a verdict. The retrial was scheduled to take place after the Court of Appeal had considered whether Letby would be granted permission to appeal her existing convictions.[127]
The retrial began on 10 June 2024.[128] On 2 July, Letby was found guilty of attempted murder,[129] and on 5 July she received a further whole‑life order.[130]
On 24 October 2024, Letby applied for permission to appeal this conviction, arguing that prejudicial media coverage should have prevented the trial from proceeding.[131] The Court of Appeal rejected the application.[132]
Further investigations and arrests
Following the verdict, police continued to investigate whether Letby had harmed other infants. Detectives reviewed around 30 cases at the Countess of Chester Hospital that had been identified as "suspicious". Neonatologists examined approximately 4,000 admissions at that hospital and at Liverpool Women's Hospital, where Letby had worked between 2012 and 2015, and were asked to refer any "unexpected and unexplained" deteriorations to police. At least one family was informed that their child’s case at Liverpool Women’s Hospital formed part of the inquiry.[40][133] Cheshire Police interviewed Letby under caution in relation to deaths at both hospitals.[134] On 2 July 2025, the Crown Prosecution Service confirmed that it was considering further charges based on new evidence provided by the police.[135]
On 4 October 2023, Cheshire Constabulary announced an investigation into potential corporate manslaughter at the Countess of Chester Hospital.[136][137] On 1 July 2025, three members of the hospital's former senior leadership team were arrested on suspicion of gross negligence manslaughter.[138]
On 20 January 2026, after reviewing evidence relating to allegations of murder involving two children and attempted murder involving seven others, the Crown Prosecution Service announced that no further charges would be brought against Letby.[139]
Thirlwall inquiry
After Letby's conviction, the British government announced an independent inquiry into "the circumstances surrounding the deaths and incidents, including how concerns raised by clinicians were dealt with".[140][141][142] It was initially established on a non‑statutory basis, meaning witnesses could not be compelled to give evidence and inquests would still be required. Senior figures at the Countess of Chester Hospital, including the medical director, chief executive and nursing director at the time of the incidents, said they would cooperate.[143][20] The medical director retired in August 2018, and the chief executive resigned the following month after signing a non‑disclosure agreement.[20]
Families represented by the law firm Slater and Gordon called for the inquiry to be given statutory powers, arguing that a non‑statutory process relied on the goodwill of witnesses.[144] Similar calls were made by former Justice Secretary Sir Robert Buckland,[145] Chester MP Samantha Dixon,[144] Steve Brine, chair of the Health and Social Care Select Committee,[146] Sir Keir Starmer, then Leader of the Opposition,[147] and the Parliamentary and Health Service Ombudsman.[148][149]
In August 2024, a group of 24 neonatal and statistical experts wrote to ministers requesting that the inquiry be postponed and its terms amended, citing concerns about the safety of Letby's convictions. The inquiry declined to make changes.[150]
Education Secretary Gillian Keegan said the type of inquiry would be reviewed once a chair was appointed.[151][152] On 30 August 2023, Health Secretary Steve Barclay announced that it would be upgraded to a statutory inquiry, enabling witnesses to be compelled to give evidence.[153]
Lady Justice Thirlwall was appointed as chair. The inquiry's terms of reference were published on 19 October 2023 and updated on 22 November 2023, when the inquiry was formally opened.[154][155]
The public hearings began on 10 September 2024. In a ruling on 29 May 2024, the chair determined that remote live viewing would be available to Core Participants, their legal representatives and the media, but not to the wider public.[156][157] During the hearings, colleagues gave evidence describing Letby as "excited and gossipy" when discussing the death of an infant, saying she preferred caring for unwell babies, complained when moved to less acute areas, and expressed eagerness for the first death of an infant to "get it out of the way".[78][158][8][159]
Former Health Secretary Jeremy Hunt apologised to families during the 2025 hearings, saying the government had taken "too long" to act.[160]
Letby's lawyers and other supporters later asked for the inquiry to be paused while her application to the Criminal Cases Review Commission was considered. Thirlwall rejected the request in March 2025 and said she intended to deliver her report in November 2025.[161]
Publication is scheduled for after Easter 2026.[162]
New defence team
In September 2024, Letby appointed a new defence lawyer, Mark McDonald. At a press conference in December 2024, McDonald said he was preparing fresh applications to both the Court of Appeal and the Criminal Cases Review Commission. He argued that the prosecution's lead expert witness, Dewi Evans, was unreliable, claiming that Evans had altered his views on how some infants had died. McDonald also said that several experts were producing reports on the infants' deaths without payment, and that two reports—relating to Children C and O—had concluded that there was no evidence of deliberate harm.[163][164]
Following the press conference, Evans rejected the criticisms, describing them as "unsubstantiated, unfounded, inaccurate". He said the only change in his evidence concerned the date of Child C's death, which he attributed to a clerical error by the prosecution.[165][166] Some of Evans's post‑trial comments about the mechanisms of death differed from positions he had taken while giving evidence at trial.[167][168][169][170]
On 4 February 2025, Letby's legal team applied for her case to be reviewed as a potential miscarriage of justice. On the same day, findings from a panel of 14 international medical experts were released. Chaired by Shoo Lee, a retired neonatologist from the University of Toronto, the panel concluded that there was no medical evidence supporting claims that Letby had deliberately harmed or murdered infants at the Countess of Chester Hospital. The panel attributed many of the deaths to natural causes or substandard care, citing issues such as inadequate staffing and delays in essential treatment, and argued that the deaths were unrelated to deliberate actions by Letby.[171]
Inquests
Inquests into the deaths of five babies were opened on 4 February 2026.[172] English law limits the verdicts available to coroners when criminal convictions have already been returned.[173]
Reactions
Calls for regulation and reform
The British Medical Association called for a formal mechanism to hold NHS managers and healthcare administrators accountable for mismanagement, comparable to the General Medical Council's ability to strike off doctors.[174] A neonatal consultant who had raised concerns about Letby also urged the introduction of regulation for healthcare management.[175]
The Parliamentary and Health Service Ombudsman, Rob Behrens, said that radical reform of NHS management was needed to prevent similar failures.[149][176] Dewi Evans called for an investigation into potential corporate manslaughter in relation to the case.[177]Dame Ruth May, NHS England's Chief Nursing Officer, stated that the NHS was committed to learning from the case and welcomed the independent inquiry announced by the Department of Health and Social Care.[178][179]
On 21 August 2023, it was announced that the nursing director at the Countess of Chester Hospital during Letby's employment had been suspended from her subsequent role at Northern Care Alliance NHS Foundation Trust, following information that emerged during the trial.[180] The Nursing and Midwifery Council later confirmed that she would face a fitness‑to‑practise investigation.[181] She and other senior executives at the hospital were accused of failing to act on warnings about Letby.[180]
It was also reported that the government was examining whether Letby's NHS pension could be forfeited.[182] NHS pension regulations allow for pensions to be withdrawn following convictions for certain offences.[183]
Safety of the convictions
Letby has consistently maintained her innocence and has continued to receive support from friends and some former colleagues.[184] A number of medical, statistical and scientific experts have also expressed doubts about the safety of her convictions.[185][186] The fact that her defence called only two witnesses at trial—Letby herself and a plumber—has been cited by some commentators as evidence that the jury did not hear a fully balanced account of the medical issues. Following the conclusion of her second trial in July 2024 and the lifting of reporting restrictions, several of these concerns were published in the press.[126][77][83] The Court of Appeal has rejected multiple arguments challenging the safety[b] of the convictions.[126]
Concerns about the medical evidence
Much of the medical evidence presented at trial has been criticised by experts across several specialties, including neonatology, pathology, nursing, biochemistry and forensic toxicology.[126][185] Points of scrutiny have included the prosecution's assertions that the infants were clinically stable before their collapses, that alternative explanations could be excluded, and that the alleged mechanisms of harm were medically plausible.[77][83] Controversy has also arisen from the fact that the original post‑mortem reports for the infants—most of whom underwent autopsy—did not identify suspicious or unnatural causes of death.[79][187]
In February 2025, a panel of 14 international experts convened by neonatologist Shoo Lee released findings from their own review of the deaths and collapses (see: §Expert panel investigation). The panel concluded that all of the incidents could be explained by natural causes, substandard care, or a combination of both, and found no evidence of deliberate harm.[188][189]
The following subsections summarise some of the concerns raised by the Lee panel and other experts.
Insulin
Experts have questioned the interpretation of blood test results used to support the allegation that Letby poisoned two infants with insulin.[126] Several specialists have argued that the type of assay used is prone to error and unsuitable for use in a criminal trial.[71] Guidance from the laboratory that performed the tests recommends confirmatory analysis with a more accurate method when exogenous insulin is suspected, but no such testing was undertaken.[77] A quality‑control check conducted by the laboratory around the same period produced a falsely elevated insulin reading; the jury was not informed of this.[190]
Other experts have suggested that, even if accurate, the results may have alternative explanations.[79][4] Professor Geoff Chase, a specialist in insulin physiology in pre‑term infants, and chemical engineer Helen Shannon concluded that the prosecution underestimated the quantity of insulin that would have been required—no missing insulin was identified—and that the pattern of results could not reliably indicate insulin administration in premature infants, whose physiology differs from that of older children and adults.[185][191]
A separate report by seven experts, including neonatologists, a forensic toxicologist, a forensic scientist and a paediatric endocrinologist, also raised concerns about the reliability of the assay, argued that the prosecution inappropriately relied on studies involving adults and older children, and highlighted alternative explanations for the infants' hypoglycaemia. Both reports have been submitted to the Criminal Cases Review Commission.[192][193] A different paediatric endocrinologist, John Gregory, has supported the prosecution's interpretation that the results were consistent with insulin administration.[194]
Air via nasogastric tube
Several neonatologists have described the allegation that Letby murdered three infants by injecting air into their stomachs via a nasogastric tube as implausible, variously calling the theory "nonsensical", "ridiculous", "fantastical" and "not practically feasible".[126] An X‑ray heavily relied upon by the prosecution in relation to Child C was taken when Letby had not been on shift since the infant's birth.[185]
After the trials, the prosecution's lead expert witness, Dewi Evans, said he no longer agreed with the prosecution's account of how Child C died and no longer believed that any of the infants were killed "as a direct result" of air injected into their stomachs.[167] The Lee panel concluded that there was no evidence that air had been forced down any infant’s nasogastric tube.[168][195]
Air embolism
The prosecution cited a 1989 study by Shoo Lee and A. K. Tanswell[196] to argue that skin discolouration observed on some infants was indicative of air embolism. After reviewing the descriptions of the discolouration, Lee said he did not consider them suggestive of air embolism and described diagnosing the condition by ruling out other causes as "a fundamental mistake of medicine".[4][197] The defence sought to call Lee as an expert witness during an appeal in 2024, but the Court of Appeal ruled his evidence inadmissible on the basis that he could have been called at trial and that the prosecution had not relied solely on skin discolouration to support the diagnosis.[126][198]
Lee has since published an updated version of his 1989 paper, arguing that venous air embolism has never been documented to cause patchy skin discolouration.[199] Abid Qazi, a former NHS paediatric surgeon whose case report was cited in a prosecution expert's analysis, reviewed one of the cases and expressed scepticism about the diagnosis, saying he believed Letby had been "a victim of the poor NHS system".[77]
The Lee panel proposed alternative explanations for the incidents attributed to air embolism and concluded that there was no evidence of the condition.[195]
Liver injury
The prosecution argued that liver damage found at the post‑mortem of Child O could only be explained by deliberate harm, contrary to the original pathologist's view that the injury was natural. A senior perinatal pathologist who later reviewed the case said she had seen similar liver injuries arise naturally and described the prosecution expert's position as "naive". Published research documents hundreds of comparable cases occurring naturally in neonates.[79]
A joint report by two neonatologists working with Letby's legal team argued that the injury was worsened when a doctor accidentally punctured the liver by misplacing a needle.[200] The prosecution pathologist and an independent expert interviewed by the BBC both said there was no evidence of needle trauma, although the BBC's expert also considered deliberate harm "unlikely".[201]
The Lee panel concluded that the doctor's needle may have penetrated the liver but considered it "highly likely" that the initial injury resulted from a traumatic delivery. They described the prosecution's blunt‑force trauma hypothesis as "implausible". [195][202][203] Neonatologist Mike Hall, who was instructed by Letby's first defence team but not called to testify, disputed the panel's traumatic‑delivery explanation but maintained that there was no evidence of deliberate harm.[201]
Dislodged breathing tube
Letby was convicted of attempting to murder Child K by dislodging her breathing tube. Experts have questioned how this conclusion was reached when no witness saw the event and accidental dislodgement is "extremely common".[204] The Lee panel argued that there was no evidence the tube had been displaced and that the infant's deterioration was instead caused by the tube being too small.[195]
A consultant testified at trial that Letby failed to raise the alarm when Child K deteriorated. After the trials, an email from the same consultant dated May 2017 was disclosed in which he wrote that Letby had called him to assist the infant during the incident.[205]
Quality of the statistical evidence
Several statisticians have criticised the prosecution’s use of data. The prosecution has been accused of relying on reasoning comparable to the Texas sharpshooter fallacy and the prosecutor's fallacy.[4][206] A shift chart presented to the jury, which appeared to place Letby at every suspicious incident, has been challenged on the grounds that the criteria for selecting incidents were unclear and potentially biased. Critics highlight, for instance, that some deaths and other incidents were left out, that non‑nursing staff were not included, and that the chart lacked contextual information such as relative shift frequency.[77][207] Others have used wider NHS data to argue that the cluster of deaths at the unit was not statistically anomalous,[208] and have proposed alternative explanations for the rise in mortality.[209][210]
During the investigation, Cheshire Police contacted Jane Hutton, a medical statistician, and signed a consultancy agreement with her. The Crown Prosecution Service later instructed police to discontinue this line of inquiry, and Hutton's planned analysis did not proceed. After the trials, she became one of the experts publicly critical of the statistical evidence, arguing that it "does not hold water".[206]
In September 2024, the Royal Statistical Society held a meeting to discuss concerns raised by its members. The prosecution's statistical evidence was strongly criticised, and comparisons were drawn with miscarriages of justice involving other nurses convicted of killing patients, including the cases of Lucia de Berk and Daniela Poggia.[207]
Staff and infrastructure issues
In May 2024, The New Yorker published a feature article by staff writer Rachel Aviv that questioned aspects of Letby's conviction. Aviv highlighted chronic staffing shortages on the unit, noting that staff were "overtaxed" and that only one specialist neonatologist was available. She also referred to hygiene concerns, including an earlier inquest finding that an infant had died in 2014 after a breathing tube was inserted incorrectly, and drainage problems that caused blocked pipes and occasional sewage backflow in sinks, issues that had been raised by the defence at trial.[4]
Aviv also discussed a 2016 review by the Royal College of Paediatrics and Child Health (RCPCH) into increased mortality on the unit. After interviewing staff, the RCPCH concluded that medical and nursing staffing levels were inadequate and that the rise in mortality in 2015 was not confined to the neonatal unit. The report described Letby as "enthusiastic, capable and committed" and noted that staff were "very upset" about her removal from clinical duties. It characterised the suspicions held by some doctors as a "subjective view with no other evidence". In its public response, the hospital acknowledged problems with "staffing, competencies, leadership, team working and culture".[4]
Because of reporting restrictions linked to Letby's impending retrial, the online version of the New Yorker article was blocked for UK readers,[211][212] a decision questioned in Parliament by Conservative MP David Davis.[213][214]
In August 2024, a leaked report revealed that the unit had experienced an outbreak of a dangerous bacterium during the period in which the infants Letby was convicted of murdering died. The outbreak had not been mentioned during the trials. Commenting on the report, medical microbiologist David Livermore argued that the outbreak offered a simpler explanation for the rise in deaths than deliberate harm.[215]
Mislabelled door swipe data
During the first trial, door‑swipe records were used to establish Letby's presence on the neonatal unit at the time of various incidents.[78] In August 2024, the Crown Prosecution Service confirmed that swipe data for one of the unit's doors had been mislabelled, with entries and exits reversed. The CPS did not confirm whether data for other doors had been correctly labelled.[216] Cheshire Police reviewed the use of the incorrect data and concluded that it had been relied upon in evidence relating to nine infants, although it played a central role only in the case of Child K, for whom Letby was not convicted at the first trial.[206]
A second door to the unit did not record entries or exits, meaning that swipe‑card data could not account for all movements into and out of the unit.[206][78]
Interpretation of handwritten notes
During the trial, handwritten notes found at Letby's home were presented by the prosecution as amounting to a confession.[84] Faye Skelton, a lecturer and specialist in forensic psychology, noted that the notes also contained statements denying guilt. She told Channel 5 that they were "perfectly plausible as the output of someone who is suffering extreme mental distress" and that she did not regard them as a confession or admission of guilt.[83]
In September 2024, The Guardian reported that the notes had been written on the advice of counsellors as part of a therapeutic process. Richard Curen, chair of the Forensic Psychotherapy Society, said that "doodling, journalling is a way of taking control of your thoughts" and that he did not consider the notes to be a confession.[86][c]
Gísli Guðjónsson, an expert in confession evidence, has written a report arguing that the notes should not be interpreted as a confession, emphasising the impact that the accusations were having on Letby's mental state at the time they were written.[217]
Criticism of witness
Several medical experts have questioned the reliability of the prosecution's expert witness, Dewi Evans. Svilena Dimitrova, an NHS consultant neonatologist, and Roger Norwich, a medico‑legal expert, submitted formal complaints to the General Medical Council regarding Evans's evidence. Dimitrova told The Guardian that she believed "the theories proposed in court were not plausible and the prosecution was full of medical inaccuracies", adding that while she could not assert Letby's innocence, she saw "no proof of guilt". Evans rejected suggestions of bias and noted that the defence could have called its own expert witnesses at trial but did not do so. Other prosecution experts broadly supported his conclusions.[126]
The New Yorker reported that in an unrelated earlier case, a Court of Appeal judge had described one of Evans's expert reports as "worthless", containing opinions that were "tendentious and partisan" and outside his professional competence.[4]
Reaction and responses to doubt
Evans has said he has received online abuse from supporters of Letby who question the safety of her convictions.[218][219] Speaking to the BBC, he compared the hostility to intimidation directed at doctors by supporters of convicted abusers in the 1980s and 1990s.[218] He argued that some people struggle to accept that a perpetrator could be "a young, white, English nurse from a respectable background" who "hid in plain sight", drawing parallels with figures such as Harold Shipman and Jimmy Savile.[218]
A barrister representing the infants' families described doubts about the convictions as "conspiracies, some of which are grossly offensive and distressing for the families of her victims". The families' legal representatives argued that the Thirlwall Inquiry should be publicly livestreamed to counter misinformation, saying that doubts "grow in the shadows". The inquiry rejected the application, concluding that livestreaming was unnecessary.[220]
BBC special correspondent Judith Moritz, one of four reporters permitted in the courtroom, told The Sunday Times that public debate about the case often overlooked the jury's experience of observing Letby. Moritz said Letby appeared tearful when discussing herself, her job loss and her relationship with a married doctor, but not "particularly" affected when the infants' deaths were discussed. By contrast, Guardian correspondent Josh Halliday reported that Letby did become tearful when discussing the infants' deaths, including during police interviews.[221][222][223] Moritz also said that Letby contradicted herself and attempted to "out‑lawyer" the prosecutor.[224] Some courtroom observers during the first trial described Letby as "aloof and indifferent" and noted her frequent claims of having no recollection of events, which they felt contributed to an impression of guilt.[198]
Expert panel investigation
During Letby’s 2022–2023 trial, the prosecution's expert witness, Dewi Evans, relied on a 1989 article by Canadian neonatologist Shoo Lee to support a diagnosis of air embolism as the mechanism of death in several cases.[196][225] Lee, who is president of the Canadian Neonatal Foundation, was not called as a witness and, living in Canada, did not learn that his research had been used in the trial until after the verdict. On becoming aware of the case, he expressed concern that his work had been misapplied.[226]
Following Letby's unsuccessful application for leave to appeal in 2024, Lee convened a panel of 14 medical experts from six countries to review all of the cases from the trials. The panel was provided with medical records and relevant witness testimony by Letby's barrister. Members accepted no payment and agreed to publish their findings regardless of whether they supported or undermined the convictions.[227] On 3 February 2025, Lee appeared at a press conference alongside Letby's barrister Mark McDonald, MP David Davis, and neonatologist Neena Modi, former president of the Royal College of Paediatrics and Child Health.[228][202] Lee stated that the panel "did not find any murders" and concluded that "in all cases, death or injury were due to natural causes or just bad medical care".[229] In parallel, Letby's legal team submitted an application to the Criminal Cases Review Commission for the case to be reviewed as a potential miscarriage of justice.[228]
In popular culture
In 2023, BBC Panorama broadcast the documentary Lucy Letby: The Nurse Who Killed, based on reporting by Judith Moritz. It first aired on BBC One on 18 August.[230][231]
In 2024, Channel 5 released two documentaries Lucy Letby: Did She Really Do It? and Letby: The New Evidence.[232] That same year, Mortitz and Jonathan Coffey published Unmasking Lucy Letby:The Untold Story of the Killer Nurse.[233]
In 2025, ITV broadcast Lucy Letby: Beyond Reasonable Doubt?,[234] while Channel 4 aired two series: Conviction:The Case of Lucy Letby and Lucy Letby: Murder or Mistake.[235]
In 2026, Netflix released a feature-length documentary titled The Investigationof Lucy Letby.[236]
↑Knapton, Sarah; Evans, Martin; Barnes, Sophie; Bolton, Will (9 July 2024). "Lucy Letby: Serial killer or a miscarriage of justice?". The Telegraph. Archived from the original on 9 July 2024. Retrieved 8 February 2025. Dr Shoo Lee: "Air embolism should never be diagnosed by exclusion. The rash she [Dr Bohin] described is not diagnostic of air embolism. Air embolism is very specific."
↑Knapton, Sarah; Evans, Martin; Barnes, Sophie; Bolton, Will (9 July 2024). "Lucy Letby: Serial killer or a miscarriage of justice?". The Telegraph. Archived from the original on 9 July 2024. Retrieved 8 February 2025. Dr Lee said experts were wrong to conclude that skin mottling was indicative of air embolism, warning that such discoloration was generic and could have been caused by a circulatory collapse.
12"Letby Sentencing Remarks"(PDF). judiciary.gov.uk. Manchester Crown Court. 21 August 2023. Archived(PDF) from the original on 24 August 2023. Retrieved 23 August 2023.
↑"Criminal Justice Bill (Eighth sitting) - Hansard - UK Parliament". hansard.parliament.uk. 16 January 2024. Retrieved 10 February 2025. [ Laura Farris ] In the past year or two, several high-profile murderers—Thomas Cashman, Jordan McSweeney, and most recently Lucy Letby—have refused to attend their sentencing hearings, causing the victims' families significant further distress. This can be seen as the final insult, and it is also the coward's approach, affronting the victims one last time by robbing their families of a chance to look them in the eye as the judge determines their fate. The worst offenders should be required to face the consequence of their actions, and hear society's condemnation expressed through the sentencing remarks of the judge. Indeed, it is with those words ringing in their ears that they should hear the prison door clang shut.
12Hammond, Philip (25 October 2024). "The Lucy Letby Case: Part 7"(PDF). Private Eye. Retrieved 6 November 2024. In August 2024, Evans withdrew his evidence on murder by splinting in a signed statement to Channel 5 declaring: 'None of the babies were killed as a direct result of the injection of air, or fluid and air deliberately injected into their stomachs.'
↑David Davis (14 May 2024). "Topical Questions". Parliamentary Debates (Hansard). Vol.750. United Kingdom: House of Commons. col.135. Retrieved 10 February 2025. Yesterday, The New Yorker published a 13,000-word inquiry into the Lucy Letby trial, which raised enormous concerns about both the logic and the competence of the statistical evidence that was a central part of the trial. The article was blocked from publication on the UK internet, I understand because of a court order. I am sure that court order was well intended, but it seems to me that it is in defiance of open justice. Will the Lord Chancellor look into this matter and report back to the House?
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