I wonder if anyone knows how Asians vote. Too bad British exit polls aren't broken up by demographic groups. 
Asians mostly vote Labour, some groups more than others. Sikhs in particular are overwhelmingly Labour. Muslims (especially Kashmiris) have usually been very Labour as well, though 2005 was a big exception in some areas because of Iraq (but things reverted back to normal as early as 2006). Hindus are a largely Labour voting group as well, though there's a sizeable Tory vote amongst middle class Hindus.
Underneath that, things can be more complicated. In some heavily Kashmiri areas the biradari system can have a powerful impact on voting patterns (though it's influence has been waning somewhat in recent years, as an increasing number of younger Kashmiris have started voting Labour for overt class reasons) even in General Elections. Bradford West was a safe Labour seat until 1997 (yeah, srsly) was regarded as a key marginal throughout the Labour government and is now essentially a safe Labour seat again...
You then have the influence that the politics of the mother country can have on voting patterns here. In most Bangladeshi areas, the Labour Party has been seen as an extension of the Awami League while Respect was often seen as an extension of Jameet-e-Islami. In Southall, Labour dominance is based on a coalition of Congress and various Communist groups. And so on.
