To be PM you have to be a MP by definition, very sad the Labour who has a massive number of MP's has no obvious contender as a MP, the favourite is currently the Mayor of Manchester. Seems the plan is for him to resign and a 'volunteer' to stand down and have a by election. Now quite how the voters will take this is another matter, he could lose.
Makes you wonder what the volunteer will be getting out of this, a Peerage?