The 1st Anti-Aircraft Division was an Air Defence formation of the British Army before and during the early years of the Second World War. It defended London during the Battle of Britain and The Blitz.
26th (London) Anti-Aircraft Brigade was an Air Defence formation of the British Army during the Second World War. It defended London during the Blitz.
The 2nd Anti-Aircraft Division was an Air Defence formation of the British Army from 1935 to 1942. It controlled anti-aircraft gun and searchlight units of the Territorial Army (TA) defending the East Midlands and East Anglia during The Blitz.
The 6th Anti-Aircraft Division was an air defence formation created within Anti-Aircraft Command of Britain's Territorial Army just before the Second World War. It defended the Thames Estuary and the approaches to London during the Battle of Britain and the Blitz.
The 3rd Anti-Aircraft Division was an air defence formation of the Territorial Army, part of the British Army, created in the period of tension before the outbreak of the Second World War. It defended Scotland and Northern Ireland during the early part of the war.
The 1st Lancashire Engineer Volunteer Corps was a Volunteer unit of Britain's Royal Engineers, first raised in 1860. It went on to spin off a unit of fortress engineers and provided a signals training centre during World War I. Its successor units provided signal support for West Lancashire Territorial Army (TA) formations in the early stages of World War II, and for Eighth Army HQ during the Second Battle of El Alamein, the advance to Tunis, invasion of Sicily and through Italy, ending the war in Austria. Postwar successor units have continued in the TA and Army Reserve to the present day.
The 4th Anti-Aircraft Division was an air defence formation of Britain's Territorial Army, created in the period of tension before the outbreak of the Second World War. It defended North West England during the Blitz.
The 7th Anti-Aircraft Division was an air defence formation of the British Army during the early years of the Second World War. It defended North East England during the Battle of Britain and The Blitz.
The 8th Anti-Aircraft Division was an air defence formation of the British Army during the early years of the Second World War. It defended South West England during The Blitz and the Luftwaffe 'hit and run' raids, but only had a short career.
The 9th Anti-Aircraft Division was an air defence formation of the British Army during the middle years of the Second World War. It defended South Wales and the Severn Valley during The Blitz but only had a short career.
The 10th Anti-Aircraft Division was an air defence formation of the British Army during the early years of the Second World War. It defended Yorkshire and Northern Lincolnshire during The Blitz and the Baedeker Blitz but only had a short career.
The 11th Anti-Aircraft Division was an air defence formation of the British Army during the early years of the Second World War. It defended the West Midlands during The Blitz, including the notorious raid on Coventry, and the subsequent Baedeker Blitz, but only had a short career.
12th Anti-Aircraft Division was an air defence formation of the British Army during the early years of the Second World War. It defended Western Scotland and Northern Ireland, including the period of the Clydebank Blitz and Belfast Blitz, but only had a short career.
3rd Anti-Aircraft Brigade was a Supplementary Reserve air defence formation of the British Army formed in Northern Ireland in 1938. On the outbreak of the Second World War it saw active service with the British Expeditionary Force during the Battle of France and Operation Aerial. It then returned to Northern Ireland and defended the Province for the next two years. Postwar, it was reformed in the Territorial Army and served until the disbandment of Anti-Aircraft Command in 1955.
44 Signal Regiment was a Territorial Army (TA) unit of the British Army's Royal Corps of Signals. It had its origins in a Volunteer unit of the Royal Engineers (RE) formed in the 1890s. It provided the divisional signals for the 44th Division and its duplicates in both World Wars, also seeing active service with 28th Division in the First World War. Its successor continued in the postwar TA and Army Reserve.
50 (Northumbrian) Signal Regiment was a Territorial Army (TA) unit of the British Army's Royal Corps of Signals. It had its origins in a signal company and a cyclist battalion formed in 1908 and it provided the divisional signals for the 50th (Northumbrian) Division and its duplicates during World War II. Its successors continued in the postwar TA until 2009.
1st Anti-Aircraft Group was a formation created by the British Army's Anti-Aircraft Command in 1942 to control anti-aircraft (AA) units defending London against Luftwaffe attacks during World War II. It continued this role into the Cold War until disbandment in 1955.
The City of London Signals was a Territorial Army unit of the British Army's Royal Corps of Signals. It had its origins in a signal company of the Royal Engineers formed in 1908 and during World War II it provided the divisional signals for the 56th (London) Division and its duplicates as well as communications for the Royal Air Force in the Middle East. Its successors continued in the postwar Territorial Army and Army Reserve until 2016.
48 Signal Regiment was a Territorial Army (TA) unit of the British Army's Royal Corps of Signals from 1920. It had its origins in a Volunteer unit of the Royal Engineers formed in 1861 and provided the communications for several infantry divisions during World War II. Postwar it went through a number of reorganisations. Its successor still serves as a squadron in today's Army Reserve.
57 Signal Squadron and its predecessors were units of the Royal Corps of Signals in Britain's Territorial Army and Army Reserve from 1939 to 2016. Its history began as part of Anti-Aircraft Command in World War II during the Battle of Britain and The Blitz, and continued postwar in various headquarters (HQ) and national communication roles.
United Kingdom 
Territorial Army 