LONDON (BLOOMBERG, AFP) - Mr Boris Johnson's government will not face a police inquiry into alleged pandemic rule-breaking parties in Downing Street unless an ongoing probe by a senior civil servant turns up evidence of criminal behaviour.

"Officers do not normally investigate breaches of coronavirus regulations when they are reported long after they are said to have taken place," London's Metropolitan Police said in an emailed statement on Thursday (Jan 13), adding that officers are in contact with the Cabinet Office over its own probe into the matter.

"If the inquiry identifies evidence of behavior that is potentially a criminal offense it will be passed to the Met for further consideration."

The police force have faced mounting pressure to begin a formal inquiry after it emerged Prime Minister Boris Johnson had attended a drinks party in May 2020 when such gatherings were in breach of regulations designed to stem the first wave of Covid-19 infections.

Mr Johnson told the House of Commons on Wednesday that he believed it was a "work" event.

Thursday's statement appears to remove one potential headache for Mr Johnson, though it also piles pressure on Ms Sue Gray, the official in charge of preparing a report on the May 2020 event as well as other gatherings in Downing Street during the pandemic.

The prime minister has said people should wait for Ms Gray's report before coming to a judgement on what happened, while many Conservative members of Parliament have said they will consider her findings before making a decision on whether they still back Mr Johnson's leadership.

On Thursday, The Telegraph newspaper reported that staff at the office of Mr Johnson drank alcohol at two leaving events during lockdown on the eve of Prince Philip’s socially-distanced funeral.

Advisers and civil servants gathered after work on April 16 last year to mark the departure of Mr James Slack, Mr Johnson’s director of communications, and one of the prime minister’s personal photographers, the paper reported.

Eye-witnesses told The Telegraph that alcohol was drunk and guests danced as the gatherings stretched late into the night.

The events came the day before Queen Elizabeth’s late husband, Prince Philip, was laid to rest, and while the country was in a period of public mourning.