I don't think "the Nasty Party" will have anything to do with impending cuts. As High Spirits notes, defence would be in the firing line whichever party won last night. Although I wouldn't be surprised if the US didn't lean on the MoD / PM to temper any further cuts.
And personally, I don't think not spending money you don't have qualifies you as "nasty", just sensible, but I suppose that's the northern working class common sense in me talking. Any one who thinks otherwise needs to wake up to the chaos spending what you don't have causes.