SUE Gray has heard “extremely damning” evidence from police officers who guarded Downing Street during lockdown parties, it has been reported.

The senior civil servant’s report is expected to be published within days, with the findings potentially fatal for Boris Johnson’s premiership.

Dominic Cummings, the Prime Minister’s former top aide, has also provided written evidence. He has said he is willing to swear "under oath" that his ex-boss lied to Parliament about parties.

"I have answered questions in writing and will answer further questions in writing if she [Gray] wants," he announced, adding: "Other damaging stories will come out until he [Johnson] is gone. It’s clear talking to people in No 10 and 70 Whitehall that many officials are desperate to shove the kunlangeta off the ice this week."

Members of the Metropolitan Police’s Parliamentary and Diplomatic Protection Command unit have provided bombshell evidence, one Downing Street source told the Telegraph.

Johnson, civil servants and political advisers have also been questioned by Gray, who has access to security pass records and the Prime Minister’s official diary.

Over the weekend The Sunday Times reported that Gray’s inquiry had been widened to cover claims of parties in Johnson’s Downing Street flat which he shares with his wife, Carrie, and their two children.

Sources on Downing Street suggested that testimony provided by officers guarding the street could prove terminal for the Prime Minister’s reign.

“Met officers have spoken to Sue Gray now, as you would expect, and have been able to provide a lot of information,” one told the Telegraph.

Explaining how damning the evidence could be, they added: “Put it this way, if Boris Johnson is still Prime Minister by the end of the week, I’d be very surprised.”

With widespread public anger and collapsing opinion poll ratings for the Conservatives – and for Johnson in particular – many Tory MPs are in a mutinous mood.

Many of the so-called “red wall” MPs – who took traditional Labour seats in the 2019 – are said to fear they now look set to lose them again in the resulting backlash against the party.

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A move against the Prime Minister looked to have been put on hold last week with the defection of Bury South MP Christian Wakeford to Labour, causing MPs to rally to the party colours.

However, the stay may be only temporary with some in No 10 fearing a flurry of letters to the chairman of the backbench 1922 Committee Sir Graham Brady when the report is published .

Under party rules, once the total reaches 54 – 15% of Tory MPs – Sir Graham must call a vote of confidence in the leader.

While Johnson may win such a vote, it would nevertheless be a further body blow to his already diminished authority, raising questions as to how long he could continue.

The Prime Minister is also contending with allegation of corruption, with Tory MPs accusing the Government of blackmail in a bid to stave off a rebellion.

Speaking to the Daily Express, Transport Secretary Grant Shapps said the Prime Minister “recognises the need for change in the Downing Street operation”.

He told the paper: “There’s no doubt in my mind that the PM regrets deeply the hurt this affair has caused. I know the last thing he would want is to offend people who have followed the rules and suffered as a consequence.”

The report may also lead to renewed calls for the Metropolitan Police to open a criminal investigation if there is clear evidence that the Covid restrictions in place at the time were breached.

Among the events Gray has been investigating is a “bring your own bottle” do in the Downing Street garden in May 2020 during the first lockdown.

Johnson has admitted he was there but said he thought it was a “work event” – an explanation that was met with widespread derision.

She has also been looking at two staff leaving dos on April 16 last year on the eve of the funeral of the Duke of Edinburgh, which have already seen No 10 apologise to Buckingham Palace.

It remains unclear what form Gray’s report will take. On Sunday Deputy Prime Minister Dominic Raab said there would be “full transparency” but declined to commit to publishing the report in full.

“The process for it will be for the Prime Minister to decide,” he said.