U.K. Prime Minister Boris Johnson witnessed weekly drinking sessions by his staff throughout the coronavirus pandemic, for which they installed a specially bought wine fridge, according to a report Saturday.

The report in the Daily Mirror newspaper caps a torrid week of revelations about lockdown breaches in Downing Street that saw Johnson's office forced Friday to apologize to Queen Elizabeth II.

The drip-feed threatens to overshadow reported plans by Johnson to relaunch his embattled premiership, starting with a relaxation of ongoing pandemic restrictions later in the month.

Whether Johnson and his staff knowingly broke the law during prior lockdowns is the central question being addressed in an inquiry by senior civil servant Sue Gray, who could report back next week.

The Daily Mirror published a photograph of the wine cooler being delivered to a back door in Downing Street in December 2020, and said staff would regularly stock it with suitcase-loads of alcohol.

"Wine-time Fridays" were scheduled into the electronic calendars of around 50 staff at Number 10, in apparent violation of a ban on indoor socializing during the pandemic, it reported.

Johnson would often drop by for a chat at the end of the working day, the newspaper said, quoting one source as saying: "The idea that he didn't know there were drinks is total nonsense.

"If the PM tells you to 'let off steam', he's basically saying this is fine."

In response, a Downing Street spokesperson said the government was awaiting Gray's inquiry "to establish the facts around the nature of gatherings" during the pandemic.

Two parties were held in April 2021 as the Queen prepared to bury Prince Philip, her husband of 73 years. Downing Street sent apologies to Buckingham Palace, calling them "deeply regrettable."

At least five Conservative MPs say they have filed letters demanding a vote of no confidence in Johnson, but he plans to launch "Operation Save Big Dog" to salvage his leadership, according to reports.

Johnson allies have been touting his achievements in office, including his delivery of Britain's Brexit withdrawal from the European Union, and The Independent newspaper said he will oversee a clear-out of top staff.

But the opposition Labour party, which has surged in the polls since the "partygate" revelations began emerging last month, said Johnson was unfit for office.

"We are witnessing the broken spectacle of a prime minister mired in deceit and deception, unable to lead," Labour leader Keir Starmer was expected to say in a speech later Saturday.