Only on Monday morning had the chairman of the so-called 1922 Committee, Graham Brady, announced that the necessary number of letters from Tory MPs for a vote of no confidence – i.e. at least 54 – had been received.

The timing of the explosive news, which is likely to have sobered up some still solemn Brits, is no coincidence: when asked, Brady indirectly confirmed that they did not want to overshadow the anniversary celebrations in honor of the Queen in the past few days.

According to party circles, the calls for a no-confidence vote were received by letter, email and even WhatsApp.

Johnson has been under domestic political pressure since it emerged bit by bit over the winter that his official home in London's Downing Street was partying excessively while the rest of Britain sat in long lockdowns and was unable to say goodbye to dying loved ones.

Party colleagues had repeatedly publicly demanded that Johnson, who tolerated the celebration culture and in some cases even participated, should resign.

However, as of Monday, the number of critics had never reached the necessary threshold to trigger the no-confidence vote - even when Johnson was fined for attending one of the parties, becoming the first sitting PM to have been shown to have opposed the vote has broken the law.

The outbreak of war in Ukraine led some critics at times to believe it was not the right time for a change in leadership.

Only the recently published investigative report by top official Sue Gray, which gave those responsible at Downing Street a devastating certificate of good conduct, encouraged other MPs to write their letters to the responsible 1922 committee and its chairman Brady.

The final straw could also have come from boos from Royal fans, who were clearly heard as Johnson arrived with his wife Carrie for the anniversary service at London's St. Paul's Cathedral on Friday.

Dangerous for Johnson: The rebellion does not seem to come from just one wing of the party, but reflects widespread discontent.

"I'm not aware of any orchestrated campaign," said 1922 Chairman Brady.