Where did you hear that??? 99.9% sure that's untrue.
Did you know that you can actually fit your own boiler including doing the gas work? Not that I would recommend it to anyone, but it's not illegal to do so in your own home.
are you joking?
you can fit a pipe yeah and maybe you're getting it ready to be used for gas but someone gas safe registered would have to commision the work and you'll find it hard to get someone out if they know you've been messing on..
but it can be done, the only trouble is, if it was me, i'd be pulling everything you had done to bits, boiler back off the wall and pipes all apart before i'd start putting my name to anything you had done..
please stop telling people its fine to work on gas while you're on..
this thread should be locked or you should be banned, you're going to get someone killed