I agree wrt. to diverting to a major airport as being a good option in case of an emergency. The CAA or ATC won't prosecute you for it and there's far more help available over there than on a dodgy farm strip.
However, diverting to, let's say, LHR when on a VFR flight in perfect VMC conditions because of a broken vacuum pump will certainly give the informal air police over at Jet Blast a field day.
They should not question the judgement of the commander, but you and I know they will.
