More from British PM's party voice call for him to resign over partygate

There is a gradual build up of members of Parliament from within the UK's ruling Conservative Party who have voiced their concerns over the partygate scandal, calling for party leader Boris Johnson to resign as Prime Minister.

The total number of openly critical MPs has risen to 26 since the publication of an inquiry report into COVID lockdown law-breaking parties at Downing Street by top civil servant Sue Gray last week.

While former UK Cabinet minister and attorney-general Jeremy Wright posted a statement on his website on Monday to say Johnson must resign "for the good of this and future governments", Tory MP Elliot Colburn said he was "appalled at the revelations of the poor treatment of security and cleaning staff".

The threshold to trigger a confidence vote against the Prime Minister is 54 letters of no-confidence, a secret process with only the chairman of the powerful 1922 Committee of backbench Tory MPs aware of the exact figure.

However, since Gray's scathing report declared leadership failures were behind a culture of rule-breaking within Downing Street and triggered yet another apology from Johnson, the rebellious voices from within his party have been slowly gaining ground.

It comes as some UK media reports claim Johnson's wife, Carrie, faces the prospect of being summoned before a House of Commons committee to explain another secret gathering in the Downing Street flat on the Prime Minister's birthday that was left out of the Gray report.

She, along with Johnson, has already been fined for a party on the day in June 2020 in the Cabinet Room but there have been reports of an informal friends' gathering with Abba music in the prime ministerial residence upstairs that has been mysteriously omitted.

The Commons' Privileges Committee, which is investigating whether Johnson knowingly misled Parliament over the gatherings, is reportedly set to consider making a request to his wife for evidence after the Opposition Labour Party called for the committee to investigate. Angela Rayner, Labour's Deputy Leader, has said Johnson "must come clean with the British people".

Meanwhile, Cabinet ministers have rallied to Johnson's defence since the publication of Gray's report and are keen to move on from the scandal.

The long-awaited report into the partygate scandal detailed examples of excessive drinking, mistreatment of cleaners and security staff, and repeated COVID rule-breaking within government offices during the pandemic, when the rules forbid mixing of different households to contain the spread of coronavirus.

The publication of the report followed the conclusion of a separate Metropolitan Police investigation into 12 lockdown parties at Downing Street and across Whitehall government offices. The Met Police handed out 126 fixed penalty notices, or fines, for rule breaches.

In Parliament last week, Johnson among those fined said he took "full responsibility" for everything that took place on his watch and that he was "humbled" by the findings.

He told MPs that when he had previously said "the rules and guidance had been followed at all times", it had been what he "believed to be true" at the time.