Obviously you will be getting or got planning and building regs approval first!!

and secondly, providing it is carried out correctly (1.2m squares alternativly spaced at a time) , and is inspected once excavated, re-bar'd up[if req'd by regs] and once poured [inc the use of non shrink grout/ally powder]

then yes you are allowed to do ityourself..

Thanks for the info. Its early days. I would definitely like to extend above the garage but due to my budget, I may only be able to extend the kitchen out to the boundary and put a pitched roof on.

Im thinking that if I do the underpinning myself, I can then employ a bricky then a roofer to get the shell up. This has got to be the cheapest way to do it???

I already know a few people that I can get in to do the job, but is there anyone on here that would be interested??? (Newcastle - North shields area)