The reopening of a police investigation into whether Sir Keir Starmer broke lockdown rules may be particularly uncomfortable for the Labour leader, in light of his calls for the Prime Minister to resign over partygate.

Sir Keir has come under pressure since footage emerged of him drinking a beer with colleagues in April 2021 in Durham, during campaigning for the Hartlepool by-election, when indoor gatherings were against the law.

Durham Constabulary on Friday said they were investigating the incident, having received “significant new information”.

It is a tricky situation for the Labour leader, who has sought to contrast his integrity with Boris Johnson’s rule-breaking.

The Prime Minister and Chancellor Rishi Sunak have been fined for breaking Covid laws and the Metropolitan Police continue to investigate at least 12 gatherings held during lockdown in Downing Street and Whitehall in 2020 and 2021.

Mr Johnson is understood to have been present at half the events being looked at.

Even before Scotland Yard launched its probe into No 10 parties, Sir Keir repeatedly called on Mr Johnson to step down.

Here is a look at some of the Labour leader’s comments on the issue.

– January 14

Following the disclosure of parties held on the eve of the Duke of Edinburgh’s funeral, Sir Keir said Mr Johnson should be offering the Queen his resignation.

He said: “The Conservatives have let Britain down. An apology isn’t the only thing the Prime Minister should be offering the palace today.

“Boris Johnson should do the decent thing and resign.”

– January 15

Sir Keir said the Prime Minister had lost his moral authority and called for the Tory party to topple him.

He said: “The moral authority matters, of course, in relation to Covid, but we’ve got other massive challenges facing this country.

“We’ve got a Prime Minister who is absent – he is literally in hiding at the moment and unable to lead, so that’s why I’ve concluded that he has got to go.

“And of course there is a party vantage in him going, but actually it is now in the national interest that he goes, so it is very important now that the Tory party does what it needs to do and gets rid of him.”

– January 25

On the day the Metropolitan Police confirmed they were investigating allegations of coronavirus rule breaches in Downing Street, Sir Keir said things are “as bad as it gets for the Prime Minister, for the Conservative Party and for the country”.

“Some of his Cabinet now need to look themselves in the mirror and ask themselves why they’re still supporting this Prime Minister.

“There’s a Metropolitan Police investigation into the goings-on in Downing Street. It’s time that some of those Cabinet members spoke out and said we’re not tolerating this any longer.”

– January 26

Sir Keir said: “We now have the shameful spectacle of a Prime Minister of the United Kingdom being subject to a police investigation, unable to lead the country, incapable of doing the right thing, and every day his Cabinet fail to speak out they become more and more complicit.”

He said Mr Johnson and his Government had “shown nothing but contempt for the decency, honesty and respect that define this country”.

– January 28

Sir Keir said the Government had been “paralysed” by the looming investigation by senior civil servant Sue Gray and the subsequent police inquiry into partygate.

“We’re in this situation where the whole of Government is paralysed because the police are looking at what the Prime Minister was getting up to in Downing Street”.

– January 31

Sir Keir tweeted: “Honesty and decency matter.

“After months of denials the Prime Minister is now under criminal investigations for breaking his own lockdown laws.

“He needs to do the decent thing and resign”.

The former director of public prosecutions also said “there can be no doubt the Prime Minister himself is now subject to criminal investigation” but “he gleefully treats what should be a mark of shame as a welcome shield”.

– February 7

When Durham Police initially cleared Sir Keir following allegations that he broke lockdown rules when drinking a beer in an office, he said it showed the “contrast” with No 10 and the partygate claims.

The Opposition leader said: “I was clear throughout that no rules were broken.

“And here’s the contrast – only last Monday we got the overview from Sue Gray, and 12 cases being referred to the Metropolitan Police in relation to the Prime Minister and the goings-on in Downing Street.

“Because the Metropolitan Police consider there was evidence not only of offences, but they were serious enough and flagrant enough to put aside their usual rule that they won’t investigate 12 months after the event.

“So that’s a huge contrast, as there always was in this case.”

– April 12

On the day the Prime Minister and Chancellor paid fines and apologised for attending Mr Johnson’s birthday bash in Downing Street during Covid restrictions, Sir Keir said the police’s decision marked the “first time in the history of our country that a prime minister has been found to be in breach of the law”.

He accused Mr Johnson of “repeatedly” lying about what happened behind the door of No 10 and said the Tory leader and Mr Sunak had “dishonoured” their office and should resign.

In view of these comments, it seems likely that Sir Keir’s Labour Party leadership could end if he were to receive a fine from Durham Police.