Baxi SOLO, New Fitted in 1991- pilot lights but will not stay on?

The hot water and central heating system was operating as normal but then we noticed that the hot water had gone cold for no apparent reason and when I checked the boiler and after ensuring that I was still calling for hot water the boiler was not firing up and there was no lit pilot- which is when i tried to light the pilot but could not keep it lit.

Jon Rob
October 2007