On 1 April 1918, the newly created RAF adopted its officer rank titles from the British Army, with Royal Naval Air Service captains and Royal Flying Corps colonels becoming colonels in the RAF. In response to the proposal that the RAF should use its own rank titles, it was suggested that the RAF might use the Royal Navy's officer ranks, with the word "air" inserted before the naval rank title. For example, the rank that later became group captain would have been "air captain". Although the Admiralty objected to this simple modification of their rank titles, it was agreed that the RAF might base many of its officer rank titles on naval officer ranks with differing pre-modifying terms. It was also suggested that RAF colonels might be entitled "bannerets" or "leaders". However, the rank title based on the Navy rank was preferred and as RAF colonels typically commanded groups the rank title group captain was chosen. The rank of group captain has been used continuously since 1 August 1919.
Although in the early years of the RAF groups were normally commanded by group captains, by the mid-1920s they were usually commanded by an air officer.
In the post-World War II period the commander of an RAF flying station or a major ground training station has typically been a group captain. More recently, expeditionary air wings have also been commanded by group captains.
- Insignia and command pennant
The rank insignia is based on the four gold bands of captains in the Royal Navy, comprising four narrow light blue bands over slightly wider black bands. This is worn on both the lower sleeves of the tunic or on the shoulders of the flying suit or the casual uniform. Group captains are the first rank in the RAF hierarchy to wear gold braid on the peak of their cap, informally known as 'scrambled egg'; however, they still wear the standard RAF officer's cap badge.
The command pennant for a group captain is similar to the one for a wing commander except that there is one broad red band in the centre. Only the wing commander and group captain command pennants are triangular in shape.
An RAF group captain's sleeve/shoulder insignia
An RAF group captain's sleeve mess insignia
An RAF group captain's command pennant
An RAF group captain's sleeve as it appears on the No. 1 dress