uk news desk: In a contest that is as unpredictable as it is extraordinary, there are a few things we can say for sure.
The momentum is with ex-Chancellor Rishi Sunak. He has by far the most support among MPs, well past the 100 threshold he needs to formally enter.

There are questions about the true level of support for former PM Boris Johnson. His backers say he has plenty but the number declared publicly is conspicuously low.

Commons leader Penny Mordaunt does not yet have anything like enough support to ensure a place in the contest.

A new prime minister could be installed as soon as tomorrow afternoon and yet we know very little detail about the policies of any contender.

But some big unknowns remain.

Will Boris Johnson stand after all? If not, will he endorse Rishi Sunak whose resignation triggered his downfall? Who will Penny Mordaunt and her supporters swing behind?

A lot is likely to unfold in the hours before the 2pm deadline for candidates to put forward their nominations on Monday.