Beginning the hunt for the next PM

"Discussing an election timetable" doesn't sound that exciting.

But the paragraph tucked into the short formal letter from Sir Graham Brady to Tory MPs all but marks the end of Theresa May's premiership and the beginning of the official hunt for the next leader of the country.

After the lines in the short note restate the prime minister's determination to get Brexit done, it confirms in black and white that after the next big vote, in the first week of June, the prime minister will make plans with the party for choosing a successor.

Right now, the expectation is that vote will be lost (although it is not impossible, of course, that Number 10 could turn it round).

And the conversation that's been arranged won't just be a gentle chat about what to do next.

Senior sources have told me that means, even though the letter doesn't spell it out, that if her Brexit plan is defeated again, Mrs May will announce she is going.

One source said it was "inconceivable" to imagine that she could stay on in those circumstances.

A cabinet minister told me it would be "out of the question".

And one of her fiercest allies said: "I don't want her to, but the pressure will be absolutely immense."

One insider close to Mrs May told me they hoped under this timetable that the prime minister could avoid the humiliation of the grassroots of her party meeting to express their lack of confidence in her at a huge meeting planned for the middle of June, which would be "horrendous".

A minister said all they wanted now was to make sure "they find a dignified exit for her".

Given that politics moves at hyperspeed, it is not beyond the bounds of possibility that the prime minister will find some way of passing the Brexit bill.

Mrs May has survived through almost impossible circumstances, time and time again.

As you know, if you've been paying attention to what we've been discussing here in the last couple of weeks (!), some of her inner circle still believe that there is a chance, even if it's slim, of agreeing some kind of process with the Labour party that allows the bill to pass.

And some ministers hope that terrible results for both the main parties in the European elections could spook MPs, somehow, into getting behind the bill in the end.

But, given that one of the main obstacles to Labour agreeing a deal with Mrs May was its fear that she wouldn't hang around for long, the fact that she has all but confirmed her departure before the summer makes an agreement even harder to see.

We are witnessing, therefore, the Tories' decades-old agonies over Europe ending the time in Number 10 of another prime minister.

And like it or not, it's the issue that's likely over the next few months to shape how the party selects the next.