The Unit
Most people know the SAS as 22 SAS, the regular regiment at Hereford. Fewer know it has a part-time half: the two Army Reserve SAS regiments, 21 SAS (Artists) in the south and 23 SAS in the north. Together they are UK Special Forces (Reserve) — citizen-soldiers held to the SAS idea, training at weekends and in blocks around civilian lives.
Their work mirrors the regiment's at reserve scale — special reconnaissance and the surveillance-and-support tasks UKSF leans on — and two things about them are genuinely unusual. One is who they let in. The other is why there are two of them at all.
Why Two?
21 and 23 exist because they grew from two entirely separate roots, decades and a country apart.
The Artists revive the SAS
The SAS was disbanded in 1945. Two years later the Army resurrected it as a Territorial unit — and the number "21" was chosen to perpetuate the two wartime regiments, 1 SAS and 2 SAS, with the 1 and 2 simply reversed. The role was handed to The Artists Rifles, a celebrated London volunteer corps raised in 1859 from painters, sculptors, musicians, actors and architects — its alumni include the war poet Wilfred Owen. So "21 SAS (Artists)" is, literally, the SAS reborn inside an artists' regiment.
The escape-and-evasion line
23 came from somewhere else entirely. It was formed in 1959 from the Reserve Reconnaissance Unit, itself the successor to MI9 — the wartime intelligence branch whose specialists ran escape and evasion across occupied Europe, getting downed airmen and POWs home. 23 carries that DNA, and it is based in the north.
National reach, two family trees
Keeping both gives the reserve SAS reach across the country — and two very different heritages: the artists of the south, the evaders of the north.
The Gate — civilians, and at 47
This is the most unusual recruiting gate in UK Special Forces. Unlike the regular 22 SAS — which only takes serving soldiers — 21 and 23 accept direct civilian entrants with no prior military service, men and women alike. And the age limit is strikingly high: a civilian can apply up to about 47½, far beyond the cut-off of almost any other special-forces unit on earth.
The logic is the reserve logic. These are part-time soldiers who keep civilian careers, and the SAS has always prized the mature, self-reliant "thinking soldier" over raw youth — exactly the person a 25-year-old assault unit can't recruit. Civilians are first sponsored through basic Army Reserve training and gain experience, before they may attempt SAS(R) Selection.
Selection
Same hills, same idea, condensed for the reserve. The path runs the SAS template on the Brecon Beacons:
Train To The Standard
SAS(R) rewards the older, self-reliant athlete who can ruck the Beacons against the clock. The Gate's Selection tier maps the run, ruck and strength base it's built on.