[BenMcr]

Originally Posted by Damien

But in this case they're saying even if a 'Government of National Unity' is formed, i.e Parliament has confidence in a different Government, he would refuse to acknowledge that. Until there is a Government the last PM remains but if Parliament says 'Hey, this is the government and this is who leads it' what compels the last PM to go?

That's covered in the link above I think:

The IfG points out that a Prime Minister who has lost a vote in such circumstances would have to choose between hanging on and hoping to regain the confidence of the House; or handing over to the leader of the Opposition,even if they seemed unlikely to be able to put together a parliamentary majority.