The Territorial and Army Volunteer Reserve of the British Army has 2 Special Air Service Reserve Regiments: 21 SAS (V); 23 SAS (V).
Applicants for selection must be male, under the age of 33 or 35 they have previous military experience. They must be a British Passport holder and pass the requisite security checks.
The first test of physical suitability is to see whether you can run 8 miles in under an hour - if you can, you can come back. Also depending on where you attend the staff might add their own little wrinkles to make the initial weed out session interesting. About 40 - 60 applicants turn up at each of the squadrons outside London, in London it is quite a few more.
Without going into specific detail, then follows about 11 months of hard work. Every two weeks you turn up on Friday evening after a shitty week at work and do not expect to see a warm bath until late on sunday. You also turn up one evening a week for a beasting and sometimes some lessons on navigation and basic fieldcraft.
You attend a two week camp, this is the test phase and some continuation training.
Once you are 'badged' as SAS you go off for basic parachute training with the Royal Air Force*, combat survival training and all sorts of other training. All in depending on if you have some previous military experience and courses under your belt it can take between 18 months and 3 years to become a fully qualified TAVR SAS Operator.
Oh yeah, out of the initial 40 - 60 that turn up at each squadron 2 or maybe 3 get through to the end. I have deliberately not posted the Headquarters or Squadron locations.
* The SAS wing is not an indicator that the individual is Military Freefall qualified. It is an indicator that the individual is basic airborne qualified, having attended the 8 jumps course with Number One Parachute Traing School RAF - for members of the TAVR the course is 7 jumps. If prior to passing SAS selection the soldier has successfully completed the military parachute course he will simply exchange the standard wings on his uniform for the SAS wings.