Theresa May is in office, but is she in power?

She's still there, just. But as a former minister says, Theresa May is prime minister tonight only because "she's locked the bunker from the inside".

She is still in office, but really, not in power.

Today she has fended off requests for meetings with Cabinet ministers - some of whom believe she has to go - seeking to avoid the confrontation altogether.

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She has also staved off more demands from backbenchers for her to quit, but only by promising that she'll meet the top brass again on Friday morning.

And just when it seemed the evening might be calming down, she's had to endure the resignation of the leader of the House of Commons.

'End game'

A few weeks ago, a minister - who was loyal up until that moment - told me we were in the "end game". Tonight, it feels like the closing moments.

Even one of the prime minister's most solid defenders told me that, come Friday morning, she knows what she is likely to have to say.

Two Cabinet ministers today told me that if she can hang on until the beginning of next month, she ought to keep going, and keep trying to move Brexit forward.

But others are now utterly convinced that she can't last beyond this weekend's European elections.

And few now would dare suggest there is any chance of bringing back her latest version of Brexit - the compromise plan launched just 24 hours ago that triggered this final push to oust her.

She has already tied her success or failure to whether she can proceed with the Brexit legislation.

If the bill fell at its first vote, so would she.

So, in simple logic, if the bill never even sees the light of day, her leadership is over.

'An ugly mess'

Her supporters want, after all this political humiliation, to engineer a dignified exit.

One MP warns if she doesn't choose a time to go very soon, it all turns into an "ugly mess".

Arguably, the Conservatives are already in that.

Mrs May's exit does not solve the party, or Parliament's fundamental problems on Brexit.

But more and more Tories, whether fairly or not, believe now it is only the departure of the prime minister that gives them any hope of avoiding making things even worse.