Boris Johnson has agreed to an internal investigation into allegations of a Covid-rule-breaking Christmas party in No 10 in the face of mounting anger at Downing Street.

The Prime Minister relented and allowed an apology of sorts when video emerged of aides joking about holding such a bash last year despite repeated official denials.

Here is a look at the fiasco which has so far led to the resignation of one senior adviser to the Government, with the prospect of further trouble on the horizon.

– What happened in Downing Street last Christmas?

The Daily Mirror was first to report last week that a festive bash took place in No 10 on December 18 last year as London was under Tier 3 restrictions.

Those measures explicitly banned Christmas lunches or parties where they are “a primarily social activity”, as a Government Twitter account pointed out to the public a day earlier.

As further sources came forward to confirm the party took place, reports said staff drank alcohol, wore Christmas jumpers and even organised Secret Santa gifts.

– How did No 10 respond?

Downing Street bluntly rejected the allegations, with official statements insisting “there was no Christmas party” and no rules were broken.

On Tuesday, Mr Johnson told reporters: “I am satisfied myself that the guidelines were followed at all times.”

– But what about that video?

Hours after the Prime Minister tried to quell allegations of wrongdoing, ITV News published damning footage that gave increased weight to reports of the party.

Leaked video showed a mock press conference held between Downing Street aides and Allegra Stratton, then Mr Johnson’s press secretary, on December 22.

In the rehearsal for televised briefings that were ultimately axed, they discussed a supposedly “fictional” Downing Street party on “Friday”, which would have been December 18.

One aide was heard saying: “It wasn’t a party, it was cheese and wine.”

“Is cheese and wine all right? It was a business meeting,” Ms Stratton replied to laughter.

She then noted “this is recorded”, adding: “This fictional party was a business meeting … and it was not socially distanced.”

– How did the Prime Minister react to the video?

Facing allegations he had lied to the public, Mr Johnson apologised for the impression caused by the footage and ordered an investigation into claims staff broke the rules.

He told Prime Minister’s Questions he was “furious” about the footage as he tasked Cabinet Secretary Simon Case to report back to him “as soon as possible”.

“But I repeat that I have been repeatedly assured since these allegations emerged that there was no party and that no Covid rules were broken, and that is what I have been repeatedly assured,” Mr Johnson added.

The Prime Minister later suggested Mr Case could go further than just reviewing the events of December 18 and “look at other things”, with other alleged gatherings in that period.

– Are the police involved?

Metropolitan Police officers reviewed the footage and a “significant amount of correspondence” about the alleged breaches but said it would not launch an investigation for the time being.

Allegra Stratton
Allegra Stratton resigned as an adviser to Boris Johnson (Jonathan Brady/PA)

The force argued this was in line with its “policy not to investigate retrospective breaches” and the current “absence of evidence”.

But the Met said it would consider any evidence found as a result of the Case enquiry.

– What happened next?

Mr Johnson warned there will be “disciplinary action” for any members of staff who broke the rules, but the first departure over the affair was not over attendance at any party.

In a tearful statement outside her north London home, Ms Stratton apologised over her remarks that “seemed to make light of the rules”.

“To all of you who lost loved ones, who endured intolerable loneliness and who struggled with your businesses, I am truly sorry and this afternoon I am offering my resignation to the Prime Minister,” she added.

– What does the public think?

Many Conservative backbenchers voiced their anger over the affair, but if anyone in Government truly believed the impact of the story would not extend past the “Westminster bubble” then polling suggested otherwise.

Not only did the saga lead TV bulletins, I’m A Celebrity co-hosts Ant McPartlin and Declan Donnelly mocked Mr Johnson over the party.

Snap polls released by Savanta ComRes and Opinium on Wednesday suggested over half of UK voters believe the Prime Minister should resign.

The figure perhaps of even more concern for Mr Johnson was that both pollsters reported a third of Tory voters also think he must go.

Many Conservative politicians are also enraged, with Scottish Tory leader Douglas Ross saying Mr Johnson should quit if he was found to have misled Parliament.

Bereaved relatives of Covid victims voiced their outrage at the Prime Minister, including Jackie Green whose mother died alone in hospital with Covid on the day of the alleged party.

She said the party made a mockery of her own decision to abide by lockdown rules despite her elderly and widowed mother’s loneliness.

“The buck stops with him (Mr Johnson), he’s ultimately responsible,” she said.

“It’s a serious breach of public trust and public confidence. And if the Government were allowed to get away with this, it would be an absolute scandal.”