Nadine Dorries has written a book about the "political assassination" of Boris Johnson and it is due to be published days before this year's Conservative Party conference.
The ally of the former prime minister has titled it "The Plot: The Political Assassination of Boris Johnson" and claims to have uncovered a "fault line" within the Conservative Party through conversations with cabinet ministers, civil servants and party officials.
The book, set to be published by HarperCollins on September 28, is billed as a story of "treachery and deceit at the heart of the Westminster machine".
It will be on bookshop shelves three days before the annual Conservative Party conference, a crucial opportunity for the Prime Minister Rishi Sunak to unite his party ahead of an imminent general election.
Former culture secretary Ms Dorries, who announced she would quit Parliament after not featuring in Boris Johnson's resignation honours list, said: "I had wanted to discover the forces behind the downfall of the prime minister.
"Instead, I found a fault line within the Conservative party stretching back decades, and a history of deception fuelled by the darkest political arts.
"If you thought that power flowed from the people into Parliament, be prepared to think again."
Ms Dorries was among eight Conservative parliamentarians recently rebuked for her conduct in relation to the Privileges Committee investigation of Mr Johnson.
The cross-party panel, which ultimately found Mr Johnson lied to MPs with his repeated denials of pandemic-era parties in Downing Street, accused his loyalists of a coordinated attempt to undermine its work.
The Privileges Committee ultimately triggered Mr Johnson's resignation from Parliament in protest at its recommendation that he should face a lengthy suspension for misleading the Commons.
His supporters attacked the Labour-led but Tory-majority panel as a "witch hunt" and "kangaroo court" - with the former PM found to be complicit in the campaign.
Ms Dorries, perhaps Mr Johnson's staunchest ally, has announced her intention to quit as an MP but is yet to do so formally as she seeks answers over the peerage she never received in his resignation honours list.
HarperCollins said The Plot aims to trace Mr Johnson's rise to power with a landslide victory in the 2019 election to his prime ministerial downfall three years later.
The former prime minister was ultimately forced out of No 10 after losing the confidence of his party following a series of political crises.
Adam Humphrey, HarperNonFiction publisher, said: "Nadine's unique vantage point, unparalleled access to sources, and innate storytelling ability will provide readers of The Plot with a rare opportunity to walk the corridors of power and understand the behind-the-scenes machinations of Westminster.
"The Plot is an urgent look at how our government really operates, and I look forward to it adding to the current political discourse."
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