Reuters did a tally of public comments from Tory MPs and found the Prime Minister will have the support of at least 145 of them. It will take 180 votes for him to survive.
The ballot is secret and -- shockingly -- politicians don't always do what they say they will.
Politics is a cutthroat game but betting markets and GBP are signalling that Boris Johnson will survive.
The results are expected at 9 pm London time.
Update: The tally is up to 155.