Boris Johnson won an extra £90m to fund London policing in return for not causing trouble at the Conservative party conference in 2011, according to claims made in Lord Ashcroft's biography of the Prime Minister.
The memoir, titled Call Me Dave, alleges that Boris Johnson was given £93 million, which enabled him to make generous pledges on policing when he ran for re-election as London mayor, in return for “no mischief” at the Conservative party conference.
It says that in 2011, Chancellor George Osborne was keen to have a quiet, conventional conference. It alleges that Boris Johnson called him, and threatened to overshadow the conference with a newspaper column, as he had done in 2009 when he called for a referendum on the Lisbon Treaty.
Johnson allegedly said that his price for not writing a similarly explosive column was £90 million extra to fund policing in London. Lord Ashcroft's book claims that Osborne agreed to hand over £93 million.
The new biography on the Prime Minister has deepened the feud between David Cameron and Lord Ashcroft, right
Mr Johnson declined a request for comment and Downing Street has refused to “dignify” the book with a response to any of the claims made in it.
Other allegations from the book, which is serialised in the Daily Mail, include a story that David Cameron once asked two KGB officers to get him cannabis during a gap year in Russia.
The book also claims that a cabinet colleague once told Cameron he was born with a silver spoon in his mouth - to which Cameron apparently replied: "No, I was born with two."
A different allegation from Cameron's early years in politics claims that after Margaret Thatcher resigned in 1990, the young Cameron hedged his bets by pledging loyalty to all three contenders in the leadership race - John Major, Michael Heseltine and Douglas Hurd.
David Cameron's biggest controversies
Other claims, such as other allegations of drug use and participation in a bizarre initiation ritual say that Thatcher never liked Cameron, and quote a number of unnamed former cabinet ministers who are claimed to believe the Prime Minister 'doesn't believe in anything'.
Lord Ashcroft's book, written with co-author Isabel Oakeshott, has made a number of allegations against the Prime Minister, and is apparently compiled from interviews with friends, colleagues and former schoolmates.
The most widely-discussed claims Cameron put his genitals in the mouth of a dead pig at an initiation ceremony for the elite Piers Gaveston dining club at Oxford University.
The pair are old rivals, having both gone to Eton and Oxford University.
Responding to this story, the Prime Minister's spokeswoman said: "I'm not intending to dignify this book by offering any comment or any PM reaction to it."
But the PM is understood to have told friends that the story is "utter nonsense".
She also said that the author "has set out his reasons for writing it," suggesting that the Prime Minister believes the book is an act of revenge for his refusal to offer Conservative donor Lord Ashcroft a top job when he became Prime Minister in 2010.
According to the BBC, the Prime Minister appeared to address Lord Ashcroft's allegation in a speech at a fundraising dinner at the Carlton Club.
He reportedly told the guests that he was forced to go to the doctor due to back pain he developed while chopping wood.
He said that the doctor told him he would need an injection in his back, and explained: "This will just be a little prick, just a stab in the back."
To this, the Prime Minister joked that it "rather summed up my day".
Call Me Dave will continue to be serialised in the Daily Mail, with the full book due to be published next month.
