21 Bn Special Air Service Regiment (Artists' Rifles) formed 1.7.1947
13.5.1950 A Squadron (Chelsea) B Squadron (Chelsea)
C Squadron (Hitchin,Herts) D Squadron (Portsmouth)
1.4.1967 21 Bn Special Air Service Regiment (Artists) (Volunteers)
A Squadron (Chelsea) B Squadron (Chelsea,later Dulwich)
C Squadron (Hitchin) D Squadron (Portsmouth,later Bramley(Basingstoke)
1994 reduced to 3 squadrons
A Squadron (Chelsea) B Squadron (Newport,Gwent - later E Squadron)
C Squadron (Portsmouth)
23 Bn Special Air Service Regiment (TA) formed 1959
HQ (London,later Birmingham) A,B,C and D Squadrons
1.4.1967 23 Bn Special Air Service Regiment (Volunteers)
A Squadron (Solihull - 1.4.1975 to Port Glasgow) B Squadron (Leeds)
C Squadron (Rotherham - 1970 to Tyneside) D Squadron (Invergowrie)
1994 reduced to 3 squadrons (HQ Birmingham)
B Squadron (Sandyford,Newcastle) D Squadron (Invergowrie,det.Glasgow -
A and D amalgamated) G Squadron (Manchester)
1.7.1999 squadrons reorganised
A Squadron (Invergowrie,Angus - det.Glasgow - redesignated D Squadron)
B Squadron (Leeds,Yorkshire - newly raised)
C Squadron (Newcastle - det.Manchester - B and G amalgamated)
21 SAS Signal Squadron,Royal Signals (TA) formed 5.7.1950 (HQ London)
served 21 SAS
322 (SAS) Signal Squadron (TA),Royal Signals formed 1.4.1961
served 21 and 23 SAS
63 (SAS) Signal Squadron (Volunteers),Royal Signals formed 1.4.1967
serves 21 and 23 SAS (HQ Portsmouth)
A Troop (Southampton) C Troop (Portsmouth)
1969 B Troop formed (Bournemouth)
1977 D Troop formed (Chichester)
September 1977 HQ moved to Thorney Island