Had the same on mine, Ford said it was fuel contamination, said it smelt like it had petrol in it ,but had run fine on the first half of the tank. It went wrong immediately after the MOT !!
They drained the tank, fitted a new filter, but it hasn't run very well since, better if I use Wynns injector lub (Halfords £5.99) so probably some damage to fuel pump.
Good luck
Trev
January 2008