Exit polls predict only 314 seats for the Conservatives
That could see GBPUSD down as Conservatives looked to extend their 331 majority and the market has broadly expected that.
The pair is down to 1.2715 in the initial reaction from 1.2950 right before the poll, a significant move down on GBPJPY and up on EURGBP as well.
Even if the Tories somehow claim the majority (exit poll underestimated them in 2015) this majority will be weak and that does not bode well for the British currency.
Interestingly Labour increased their number of seats but it’s hard to see any coalition from this mix.