Sue Gray report into lockdown-breaking parties so damning it could 'end' Boris Johnson's career, official claims

• Sue Gray's report is so damning Boris Johnson may have to quit, an official has told The Times.
• The civil servant's report will be published once the Metropolitan Police probe is concluded.

Sue Gray's report into the lockdown-breaking parties in Downing Street and Whitehall will be so damaging that Boris Johnson may have to resign, an official has said.

The inquiry being carried out by the senior civil servant will be published after the Metropolitan Police finishes issuing fines and completes its investigation. The force has said it will not be sharing details of fines being handed out until after local elections on May 5.

A senior official told the Times described Gray's full report as "excoriating" and likely to "make things incredibly difficult for the prime minister."

"There's an immense amount of pressure on [Sue Gray] — her report could be enough to end him. No official has ever been in a position like this before," the source said.

Johnson has already received a £50 fixed penalty notice for attending a party to mark his birthday, held in breach of coronavirus measures in force at the time, which he had widely promoted.

Several Tory backbenchers have called for Johnson to quit over the row. But despite the fine and mounting political pressure, he has refused to resign.

On Friday, the Met issued further fines to officials who attended a "bring your own booze" party. Johnson has admitted to attending this event too, but Downing Street said he had not received a fine for this yet.

Gray issued an interim report at the end of January which was indirectly critical of Johnson, noting "failures of leadership and judgment by different parts of No 10 and the Cabinet Office at different times."

Her final report will be more directly critical of Johnson, The Times reported.