Dominic Cummings is to give a statement about accusations he broke the lockdown, as at least 20 Conservative MPs urged Boris Johnson to make him quit or apologise. In an unprecedented move for a senior political adviser, Cummings is likely to address criticism of his actions and take questions on Monday afternoon, following an outpouring of anger among the public, MPs, bishops, police, scientists and medics. The prime minister backed his senior aide at a defiant press conference on Sunday, saying it had been within the rules for Cummings to drive his family 264 miles to his parents’ estate in Durham while his wife was suffering from coronavirus symptoms. Johnson claimed his adviser had acted “responsibly, legally, and with integrity” and had followed his instincts as a father by travelling to seek possible backup childcare for his four-year-old son. Anger among Conservative MPs is boiling over, however, and members of the public have been sending furious emails pointing out the sacrifices they have made during the lockdown. Downing Street is still to answer questions, including whether Cummings stopped at any service stations en route to Durham, potentially infecting other travellers when the whole family should have been in isolation, and whether he later made a 30-mile day trip from Durham to Barnard Castle with his family at a time when non-essential journeys were banned. No 10 confirmed that Cummings would give a statement and take questions on Monday but did not say when. The prime minister was due to hold a cabinet meeting on Monday to discuss the lifting of the lockdown but plans to ease restrictions, such as partially opening schools from 1 June, have been overshadowed by the affair. On Monday morning, one Tory MP, David Warburton, described how his father had died alone as a result of following the rules, and said Cummings’s actions gave the impression of “double standards”. He told BBC Breakfast: “People have made sacrifices, this is a difficult time, this is a time of national crisis. “In those sacrifices there really hasn’t been the choice to use instinct. Instinct hasn’t really been part of it. We’ve been tasked with following regulations laid down by the government.” Other Conservative MPs to speak out included Martin Vickers, the MP for Cleethorpes, who told Sky News Cummings should resign for having “undermined the government’s message”, and Tim Loughton, a former minister, who told the BBC: “Has the action of Dominic Cummings threatened to undermine the message of the government and its ability to carry on its work? I’m afraid regretfully it has and that’s got to be dealt with.” Other Tory MPs appeared to be engaging in an effort by the party’s whips to dampen down public anger by issuing nearly identical cut-and-paste messages asking constituents to “rest assured” they are passing on concerns about Cummings to the “relevant colleagues”. Cummings has maintained a defiant position throughout, telling reporters outside his home over the weekend: “Who cares about good looks? It’s a question of doing the right thing.” He added: “It’s not about what you guys think.” The prime minister’s aide faces a possible police investigation under health laws over a claim that he breached self-isolation rules by allegedly visiting Barnard Castle on 12 April. Durham police have yet to respond to the complaints from the public but the Guardian understands the force is considering whether it needs to take any further action in relation to Cummings. However, Steve White, the acting police, crime and victims’ commissioner for Durham, will on Monday ask the force to investigate all the claims about the prime minister’s principal adviser’s time in the Durham area during the coronavirus lockdown and establish the facts. Gavin Williamson, the education secretary, was sent out to defend the adviser in the media on Monday morning, despite admitting he had not spoken to Cummings to find out the details of the trip. He said Johnson had been “categorically assured” that Cummings and family had “followed the guidance and … the law”. “If you have been given that absolute assurance … it seems fair to support that person,” he said. The Labour leader, Sir Keir Starmer, has said in Johnson’s position he would have sacked Cummings and has called for a Cabinet Office inquiry. Nicola Sturgeon, Scotland’s first minister, added her voice to the criticism on Monday. Speaking on BBC Breakfast, she said: “I fear, and I say this with a heavy heart, Boris Johnson is putting his political interest ahead of the public interest. “And when trust in a public health message and public health advice is as important as it is right now the consequences of that could be serious. I hope that the prime minister will reflect further today and perhaps come to a different conclusion than the one he made yesterday.” Some scientific advisers and Church of England bishops also expressed anger at Cummings’s actions for undermining the lockdown. Three members of SPI-B, the Sage subcommittee providing advice from behavioural scientists to the government on how the public might respond to lockdown measures, reacted with disdain to Johnson’s defence of his adviser. Martin Surl, Gloucestershire’s independent police and crime commissioner, told BBC Radio 4’s Today programme that Cummings’s actions made a “mockery” of police enforcement earlier in the lockdown. “I think it makes it much harder for the police going forward – this will be quoted back at them time and time again when they try to enforce the new rules,” he said. “But I think more importantly it makes something of a mockery of the police action going back when the message was very, very clear: stay at home. “The police had to deliver a very harsh, very difficult message and now it appears people could act differently, so I think it does undermine the policing going back and their confidence and going forward it will be more difficult but they will cope, they always do.” Tory MPs publicly criticising Dominic Cummings Steve Baker Simon Hoare Damian Collins Sir Roger Gale Peter Bone Caroline Nokes Craig Whittaker Julian Sturdy Robert Syms Paul Maynard James Gray Robert Goodwill Andrew Jones Tim Loughton David Warburton Robert Halfon Jason McCartney Martin Vickers Peter Aldous George Freeman John Stevenson