21 SAS (V) Artists. The original post WW2 SAS Regt. and the parent unit of that enfant terrible : 22. Basically created to provide a strategic reconnaissance role in the event of The Big One (WW3). Recruits can come from all walks of life (though are all soft southern poofters compared to 23 SAS(V)) and undergo a slightly easier Selection than their regular counterparts - though it is still not as hard as the fabled Army Catering Corps selection course, which nobody has yet passed. 21 SAS are trained to operate at weekends when "THEM" are too busy mowing the lawn, creosoting the fence etc - if the Iranian Embassy siege had been on a Sunday, 21SAS would have done the job.
Hated by all regular hooligans because they think that the TA boys are wearing the beret that should only rightfully be worn by them. Even though 21 is the parent unit. In reality 21 and 23 SAS(V) are very well trained and committed guys who are as well trained as a regular recce platoon but with access to more kit. This is also the back door (in the polite sense) method of entry to the regulars. This is also where old lags from 22 go to die before they retire.