Theresa May asked Boris Johnson if he planned to topple her before deciding to stay as PM, book claims

'Can I count on your support or do you intend to stand against me?' the Prime Minister is said to have asked her Foreign Secretary - and rival

Theresa May campaigned believing the election would be won - but 'broke down and wept' when the gamble backfired (Getty)

Theresa May asked Boris Johnson if he would try to topple her before deciding to stay on at No 10 after her election debacle, a new book claims.

The beleaguered Prime Minister telephoned the man seen as the biggest danger to her survival, to force the Foreign Secretary to put his cards on the table, it reveals.

The call came early on June 9, as Ms May was reeling from the bitter realisation that her election gamble had destroyed the Conservatives’ majority in the Commons.

The book claims: “According to one witness, May tells Johnson: “It's not the result we hoped for, but I intend to form a government.

“Can I count on your support or do you intend to stand against me?” Johnson makes it clear that he will be staunchly loyal.”

The Prime Minister also sought and received the same pledge from David Davis, the Brexit Secretary, according to the book, called Betting The House, by political journalists Tim Ross and Tom McTague.

Earlier, Mr Johnson had sent a text message, “expressing his backing and sympathies”, telling Ms May to keep her “chin up”, adding, “we are with you and behind you”.

The book says: “She is so delighted by the text message that she holds up her phone and shows it to her advisers.”

Since her June disappointment, the Prime Minister has denied the rumour that she discussed whether to resign even as the election results rolled in.

But the book claims Nick Timothy, her former chief of staff who himself resigned, believed she should consider stepping down and that even her distraught husband, Philip, wondered if she should go.

It also argues that:

• Mr Davis “pushed” a very reluctant Ms May into staging the early election, because he was desperate to delay the following one until 2022 – three years after Brexit.

The Brexit Secretary is said to have feared the EU forcing him to accept a poor Brexit deal in 2019, on the brink of an election the following year.

“David wanted an election and set about getting one,” says the book, adding: “When a stunned [Lynton] Crosby disagreed, Davis bragged: 'I'm persuading her.'”

• Fiona Hill, the Prime Minister’s adviser, received a leak of the astonishing exit poll, predicting a hung parliament before it was broadcast at 10pm on election night.

“It is a contact from the BBC, tipping her off about the exit poll results,” the book reads. “Hill grabs Timothy and pulls him into a side room off the main floor.

“'I've just heard the exit poll - they're predicting a hung parliament,' she says. 'Are you winding me up?' Timothy asks.”

• Conservative headquarters received an election-night phone call from Barack Obama, who had been told by a Labour contact that the party was going to lose 20 or 30 seats.

The book says: “Obama told a Tory friend to pass on an encouraging message: Labour are expecting to lose seats, meaning the Tory majority will go up. And the disastrous Corbyn is here to stay.”

• Chancellor Philip Hammond was livid at being excluded from the election campaign and regarded May's manifesto as “economic degeneracy”.

When Ms May was told of the damning exit poll – by her husband – “it took a minute for her to understand the scale of the disaster but, when she did, a devastated May broke down and wept”.