Boris Johnson has been contacted by the Metropolitan Police as part of the probe into lockdown-busting parties held in Downing Street and across Whitehall.

A questionnaire on the partygate scandal has been sent to the prime minister from Scotland Yard. It is understood to have been received late on Friday evening.

A Number 10 spokesperson said: “We can confirm the prime minister has received a questionnaire from the Metropolitan Police. He will respond as required.”

PM told it will be ‘tough’ to remain if he’s fined

The news came after Mr Johnson had been delivered a warning by a senior Conservative MP that he would find it “very tough” to remain in office if police issue him with a fine as a result of their investigation.

Speaking to the i newspaper, Tory ex-leader Sir Iain Duncan Smith said it “will be difficult” for Mr Johnson if he is handed a Fixed Penalty Notice (FPN).

“I think it would be very tough for anyone to remain after that,” he said.

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“If you’ve set the laws, and you break them and the police decide you have broken them… and then there’s the unredacted [Sue Gray] report – the two things will come together.”

Sir Iain added that the prime minister receiving a fine is “clearly not helpful”, continuing: “It will be difficult, he knows that.”

Meanwhile, Mr Johnson’s estranged former chief adviser, Dominic Cummings, posted on Twitter on Friday night: “great work tory mps leaving this crippled joke of a pm spending next 7 days bunkered down with lawyers trying to remember all his different lies while another major global crisis unfolds.”

More than 50 people to be contacted by Met Police

Earlier in the week, Scotland Yard announced its officers were to begin contacting more than 50 people believed to have been involved in the 12 events under its investigation – which has been named Operation Hillman.

The Met Police said its officers would start getting in touch with the relevant people by the end of the week as they progressed their investigation “at pace”. Those contacted are being asked to initially fill out a questionnaire.

Just days ago a fresh photo emerged of Mr Johnson at a Christmas quiz in Number 10.

The Metropolitan Police is now rethinking its assessment of that event after the publication of the image of the prime minister next to an opened bottle of alcohol, crisps, a person wearing tinsel and another wearing a Santa hat.

At the time of the event, on 15 December 2020, London was under Tier 2 coronavirus restrictions.

This banned any social mixing indoors between people from different households.

Scotland Yard said: “The Metropolitan Police service previously assessed this event and determined that on the basis of the evidence available at that time, it did not meet the threshold for criminal investigation.

“That assessment is now being reviewed.”

This has led to the possibility of a 13th event being added to the Met Police’s investigation.

Although the 15 December event was previously not among the allegations of COVID rule-breaking in Number 10 being investigated by the Met Police, it did form part of the partygate inquiry by senior civil servant Sue Gray.

She has yet to publish her full findings due to the ongoing Met Police inquiry into 12 other alleged lockdown-busting gatherings, but her initial report said that parties at Number 10 represented a “serious failure” and were “difficult to justify”.

Ms Gray has handed more than 300 images and more than 500 pages of information to Scotland Yard.