/// Gordon's last act of pique was to go and resign before the Conservative/Liberal pact was fully ironed out forcing their hand early.///
He resigned before the Conservative/Liberal pact was fully ironed out because he knew that Clegg would not climb into bed with Labour while Brown was laying in it. So he hoped that if he resigned, the Lib-Dems would go over to Labour.
I bet he is spitting feathers now, he could have still been 'Leader of the Opposition' now, instead of out of work.