The policing minister, Kit Malthouse, has said if Keir Starmer were to resign over an alleged breach of lockdown rules it does not automatically mean the prime minister should do the same. In a statement on Monday, the Labour leader said he would do the “right thing” if he was issued with a fixed-penalty notice in relation to a gathering in Labour offices in Durham in April last year. The move has been viewed as a huge gamble, with Starmer placing his future in the hands of Durham police after it was announced last week officers would reopen an investigation into the event at which he drank beer and ate a takeaway curry. However, Labour sources have said they are confident they can prove it was a work event and that those present were taking a break to eat while working late on preparations for the Hartlepool byelection. The Guardian revealed Labour has compiled time-stamped logs of WhatsApp chats, documents and video edits – which it will provide to Durham police for their investigation. Asked on LBC if Johnson should follow suit if the Labour leader was issued with a penalty and does resign, Malthouse, a longtime ally of Boris Johnson, said: “Not necessarily, no.” He told LBC: “Obviously in any situation where, you know, the rules were moving around, there were misunderstandings or mistakes were made, and apologies are made and they are accepted, then people of all walks of life should be able to keep their jobs. But Keir Starmer has to speak for himself and set his own standards.” Johnson’s spokesperson later echoed this view, saying the prime minister did not see the need to follow Starmer’s example over resignation if found to have breached Covid laws. “The prime minister’s position hasn’t changed,” he said. “Obviously, he came to the house and took responsibility and offered a full, unreserved apology for the mistakes made.” The spokesperson added: “I’m not going to get drawn into what other individuals should do.” Starmer’s critics have suggested he is attempting to put pressure on Durham police as the force would not want to be seen as in effect ending his tenure as Labour leader. Malthouse told Sky News the police force would meet “high standards” regardless of any alleged pressure. “Durham police will operate professionally to the high standards we expect of them irrespective of what the external goings-on are around this case,” he said. “We need to leave them the space and time to do their job.” Ken Macdonald – a former director of public prosecutions like Starmer – has said the suggestion Durham police would be pressured in their investigation was “wide of the mark”. The crossbench peer told BBC Radio 4’s Today programme: “My experience of working with the police in very sensitive cases under full glare of public and press interest was that, very quickly, you find your focus taking over and, in a sense, a sort of bloody-mindedness creeps in: ‘This is my case and I’ll decide it, thank you very much, without any help from you.’” In his statement on Monday, Starmer said repeatedly no rules had been broken as he sought to contrast his actions with those of Johnson, who has refused to quit after being issued with a fixed-penalty notice by the Metropolitan police over a gathering in No 10 in June 2020 to mark his 56th birthday. But having called for Johnson to go for breaking the law, many at Westminster believe Starmer will have no choice but to fall on his sword if found to have done so himself. Labour’s deputy leader, Angela Rayner, who was also present at the Durham event, has said she too will stand down if she is issued with a penalty notice.