How to join the SAS in the British Army?

you enlist in the regular British Army.......no one regiment has a better chance than the other, of course if you go R,E,M,E, or Cook then not much chance of you being recognised and invited to join the SAS.....you go on several invites / trainer weeks and from this you are informed if you are selected or not...............not every one makes it on the 1st try out [they used to allow you to try out twice but that was it after failing those two times]