Re: What will happen during a war?
"Can we rule out the Commonwealth?"
Pakistan and India are both members of the Commonwealth. Both have nuclear missiles and have been at each others throats since 1947.
Of the two Pakistan would seem the more likely to be politically destabilised into attacking the UK.
However - the politics of India are also on the trend of being populist - with hard line nationalistic religious pressures. With a population and land area much larger than the UK - and possibly less infrastructure dependency - then they might hope to "win" a nuclear exchange.