Now we know why there was such a gap between Nadine Dorries announcing she was quitting as MP for Mid-Bedfordshire, and formally submitting her resignation letter. She used the time to sharpen her attacks on Rishi Sunak.

What a letter. Ooft. In politics, the person resigning usually tries to cloak their criticisms in velvety words and phrases. The tone is more in sorrow than anger. Think of Sajid Javid’s letter to Boris Johnson (“the country needs a strong and principled Conservative Party”), or indeed Mr Sunak’s (“The public rightly expect government to be conducted properly, competently and seriously”).

Ms Dorries, a former Culture Secretary, rejected a rapier as her weapon of choice and instead came out like Scarface, all guns blazing. “Who would vote for this government?” she asked the Prime Minister in a line destined for a billboard some day.

Not content with a brutal letter, Ms Dorries has a book out next month that is set to be highly critical of the Prime Minister. The Plot: the Political Assassination of Boris Johnson promises to reveal “the shocking truth about powerful forces operating behind the scenes in the heart of Westminster”.

Ms Dorries’ book is released, like a bat from the belfry, on September 28. In the meantime, Theresa May brings together her thoughts on government in a new book, The Abuse of Power, out on September 14.

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Both titles are out in time for the Conservative Party conference in Manchester on October 1-4. Yes, it is getting close to that time of year again when cities find themselves taken over by political parties and their camp followers in the media.

This year’s conferences are attracting particular attention because they could be the parties’ last major outings before a general election in 2024. When in 2024 depends which way the wind happens to be blowing on any particular day.

There has been speculation around November, allowing more time for the economy to recover. November comes with all the usual warnings about turnout. That said, the 2019 election took place on December 12.

A disastrous result in the Mid-Bedfordshire by-election (Conservative majority 24,664) might influence timing. The writ for the by-election could be moved as soon as September 4, when the Commons returns from summer recess. A by-election must then take place between 21 and 27 days later.

The clock starts ticking when the writ is issued. This is usually within three months of a vacancy arising (longer is rare but not unknown). In Ms Dorries' case, will the vacancy date be June 9, when she announced her resignation “with immediate effect”, or the date on the letter released on Saturday?

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With a general election so close, this year’s party conferences are taking on added importance. This is the time to put the good stuff in the shop window and hide or bury the rest. Trading has been going on all summer.

Among the main parties, the Liberal Democrats are the first on the conference timetable. The gathering in Bournemouth from September 23-26 should find the party on a high following its recent by-election victory in Somerton and Frome.

Next it is Labour’s turn. As the party gathers In Liverpool from October 8-11, expect pressure from unions over pay and strikes, and from the conference in general over a Starmer government’s spending plans.

Internal criticism of Sir Keir for keeping the two-child benefit cap could erupt into the open. The leadership won’t mind if the message coming out of the conference is “stability, stability, stability”, but the rank and file need something to keep their spirits up during what could be a long wait ahead. At the moment, all Sir Keir and Shadow Chancellor Rachel Reeves seem to do is take commitments off the table.

For the Conservatives in Manchester, the only way is up. Last year’s conference in Birmingham saw the wheels come off the Truss government in spectacular fashion, leading to a Sunak takeover within the month.

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While this will be Mr Sunak’s first annual conference as Prime Minister it is unlikely to be a victory rally, with pressure on him to cut taxes and be bolder in general. Expect big turnouts in the hall for speeches by Kemi Badenoch, Suella Braverman, and Penny Mordaunt. Jokes about the latter’s sword-carrying skills are likely to feature heavily.

Finally, the SNP are in Aberdeen from October 15-17, where the leadership expects to come under pressure over its pact with the Greens. As for whether a certain police inquiry into party finances will have concluded by then, that is just one of several known unknowns ahead.

Roll on autumn.