A campaign for a new investigation into Dominic Cummings over alleged breaches of the lockdown rules has been launched by lawyers with the backing of health workers and some families of coronavirus victims. The law firm Hodge Jones & Allen, which specialises in human rights and civil liberties, said the move was part of a “citizens’ bid” for a thorough investigation into Cummings over his trips to Durham and Barnard Castle. One of the firm’s partners, Mike Schwarz, says a three-day investigation by Durham police last month was flawed after it found that no further action was required. He is heading a legal team that is calling for a specialist unit from the Metropolitan police to investigate Cummings’ behaviour during the lockdown. It will also press for the Crown Prosecution Service to consider a public prosecution. If these routes fail, the campaign is considering a private prosecution against Boris Johnson’s chief adviser. Schwarz said: “The focus has been so heavily centred on Durham, but the Met have yet to examine properly, if at all, the original breach and all his surrounding activity, in London and beyond his journey to stay in the north-east.” He added: “The broad consensus of public opinion is that he broke the law on public health, and the entire weight of the state has been deployed to prevent proper investigation and proper due process.” The initial three-day investigation by Durham police into Cummings’ travels found that he might have breached health protection regulations when he took a 52-mile round trip to the town of Barnard Castle, County Durham, with his wife and son on her birthday. But it said Cummings’ 516-mile round trip from London to Durham and back had not broken health protection regulations. The force decided to take no further action after making no finding in relation to “stay at home” government guidance. Schwarz argued that under the coronavirus regulations, Cummings had failed to leave home for a good reason. He said the campaign would encourage Durham police to explain their investigation. “It seems clear even from what they have said that they were rushed, the wrong criteria were applied, there was an incomplete examination of evidence and actions taken.” He also believes other aspects of Cummings’ behaviour warrant investigation, including his decision to return to work on 27 March after tending to his wife, who was showing symptoms of coronavirus Schwarz said Durham police’s investigation had taken no account of the damage to public trust in the government’s health message caused by Cummings’ actions. He said: “I have no desire to cast doubt on the integrity of Durham police, but it is clear they were operating in a highly charged political environment, and we want to know exactly what they did to establish what Cummings did in Durham, given the many inconsistencies in his own account.” Those backing the campaign include Andy Toogood, a mental health nurse from Hull, Dr Caroline Dickinson, a London GP, and Seamus McNally from Newmarket, whose family was unable to say goodbye to his father-in-law before he died of coronavirus. The campaign includes the barrister Matthew Ryder, who is a member of the Scott Trust, which owns the Guardian Media Group.