Labour activists in Durham have called on a Conservative MP to withdraw allegations made to the police, accusing him of presenting misleading evidence about Keir Starmer. The move was backed by the dean of Durham University’s law school, Prof Thom Brooks, who said the evidence provided by the Conservative MP Richard Holden in a letter to Durham constabulary appeared to have been proven incorrect. The chair of the City of Durham Labour party, Sheila Williams, said the allegations were “wasting police time”, including referring to a quiz and social event as being in-person when there was reference to a Zoom link. Police are investigating claims that the Labour leader broke Covid-19 rules at a gathering of staff at Durham Miners’ Hall during an election campaign in April last year, where a takeaway was ordered and Starmer was filmed drinking a beer. Labour has claimed the food was necessary for staff who were eating while they worked, and has compiled evidence for police that work continued until later that night. However, at least one witness has told the Guardian they are certain Starmer himself did not continue working in the hall after finishing the takeaway curry. The investigation by Durham constabulary will hinge on whether the gathering of campaign aides and staffers from the local MP’s office was necessary for work. Starmer has said he will resign if he receives a fixed-penalty notice. Holden has been a key figure in highlighting apparent inconsistencies in Starmer’s version of events around so-called Beergate. The Tory MP previously published one letter he sent to Durham constabulary, in which he claimed to have two new pieces of evidence for them to investigate. The first was a Facebook invitation to a quiz and social on the night Starmer was filmed, which Holden said “clearly shows” a gathering was intended to take place. The other was a Facebook message from the Labour MP for City of Durham, Mary Foy, who encouraged members to have a “greasy night”, which Holden said was a slang term for drinking too much. He said that it “appears to link the event to images of Keir Starmer drinking beer on the evening in question”. He said the messages suggest “a pre-planned in-person social event … attended by the leader of the opposition”. However, in a furious letter to the Tory MP, Williams, the chair of City of Durham Labour party, said members were being unfairly maligned and police provided with misleading information. Williams said “greasy” was “clearly a typographical error” where Foy had meant to type “great” and that the spelling error was pointed out on the Facebook post itself. She said the invitation to the quiz and social also made it clear a Zoom link would follow. “You have accused me as chair … and other officers of party of wilfully and purposefully conspiring to breach the Covid lockdown regulations that existed at that time. You, by implication, have accused all our members who attended that event of breaking the law,” she wrote. “If you had carried out even the most basic investigations, you would have discovered that you were wasting police time by asking them to investigate whether or not Keir Starmer attended the event … You brazenly did this knowing you had no evidence to prove your assertion to the chief constable.” Williams demanded a “full and unequivocal apology” from Holden and said he should tell the police that his report was “based on conjecture”. Brooks, the Durham University law professor, said: “The ‘new’ evidence of a possible breach is nothing of the sort. It concerns an online event held within the rules and raises no questions to answer. I expect the police will find no merit in these allegations when their investigation concludes.” Brooks, who has previously campaigned for the Labour party, said he did not believe Durham constabulary would find that Starmer had broken the rules. “It was no breach of lockdown rules at that time to host an online event as described. Nor is it a breach of lockdown rules at that time for those working together during an election campaign to have a meal,” he said. Holden said Durham constabulary themselves said they had received “significant new evidence” about the Labour leader’s movements that evening. He added that there had been a number of inaccuracies in Labour’s own version, including the presence of the party’s deputy leader, Angela Rayner. “It’s vital that important questions are answered too, after clear inaccuracies – such as who and the number of people present and the nature of the gathering – were made by the Labour party and Labour leader at earlier points,” he said. “Fundamentally, it is vital that the words and actions of the leader of the opposition receive the same scrutiny and inquiry as the actions of those he has spent the best part of a year focusing his efforts on have received. Given there is now an ongoing police investigation, I think it is now vital that the police are allowed to get on with their important work.”