The Air Defence of Great Britain (ADGB) refers to two different components of the RAF depending on the time period in question. The Royal Air Force (often abbreviated to RAF) is the air force branch of the British Armed Forces. ...

The first ADGB was created in 1925 as the command responsible for home defences, both fighters and bombers. It was divided into two areas controlling regular squadrons, the Wessex Bombing Area and the Fighting Area. In 1936 ADGB was abolished with the Bombing Area becoming Bomber Command and the Fighting Area becoming Fighter Command. RAF Bomber Command was the organisation that controlled the RAFs bomber forces. ... Fighter Command was one of three functional commands that dominated the public perception of the RAF for much of the mid-20th century. ...

The second use for the name came when it was adopted for the rump of Fighter Command dedicated to the defence of the United Kingdom after the formation of the Second Tactical Air Force in 1943. It was Fighter Command in all but name, and this was finally reflected in 1944 with a return to the previous name. The RAFs Second Tactical Air Force was one of the major commands of the Royal Air Force during World War II. It was formed in June 1943 in connection with preparations then in train to invade Europe a year later. ...