Durham police have confirmed for the first time they are assessing a dossier from a former senior prosecutor that says Dominic Cummings should face charges over his account of his movements during lockdown. For months Durham constabulary has refused to investigate the prime minister’s former chief aide beyond the three-day inquiry it conducted in May. But on Friday it said officers were examining new evidence submitted in a 225-page dossier more than a month ago. The documents, compiled by lawyers for the former north-west chief prosecutor Nazir Afzal, allege that Cummings perverted the course of justice in relation to his Downing Street rose garden statement about his journeys to the north-east of England in March and April. The Met police, which also received the dossier and was urged to investigate, told Afzal’s lawyers that the issues raised were matters for Durham constabulary – “notably the allegation of perverting the course of justice”. Durham police has not ruled out charging Cummings for perverting the course of justice. A spokesman for Durham constabulary said: “A report was submitted to Durham constabulary at the end of October and we are continuing to consider its contents.” It is understood that a senior investigating officer has been appointed. This marks a change in approach from the force, which had said nothing publicly about Cummings since a 391-word press release issued on 28 May following a three-day investigation in to Cummings’s movements. That statement said Cummings may have breached lockdown rules by travelling to Barnard Castle on 12 April, but the force decided to take no further action and it made no finding on his decision to leave London for Durham. At the time the force also said there was “insufficient evidence” that Cummings travelled to Durham a second time on 19 April, as initially one witness told the Guardian and the Mirror. In his rose garden statement Cummings claimed he had evidence that proved he was in London that day. Boris Johnson told MPs that he had seen that evidence, but No 10 has refused repeated requests to release it. In August the Guardian and the Mirror revealed that four people had claimed seeing someone they believed to be Cummings in woods near Durham on the morning of 19 April. They included Dave and Clare Edwards, who gave statements to the police about the sighting at the same time Cummings was giving his rose garden statement. The submissions from Afzal’s lawyers said Cummings’ account appeared to have influenced Durham constabulary’s initial investigation. It included statements from witnesses, including the Edwardses, which questioned the conclusions of Durham police about Cummings’ movements. It also included statements from at least three people in Barnard Castle, which raised doubts about Cummings’ claim that he was only there for 15 minutes and strayed no more than 15 metres from his car. The dossier also accuses Cummings and his wife, Mary Wakefield, of multiple offences under the coronavirus regulations for leaving their primary home in London and their second home in Durham without, it says, a reasonable excuse. Afzal said: “It appears that, to their credit, Durham police have taken seriously the evidence and allegations contained within our report, including the very serious allegation that he perverted the course of justice. We remain concerned that nobody should be above the law and police and prosecutors should follow wherever the evidence takes them.” Last month Cummings resigned as Boris Johnson’s chief aide, following an internal Downing Street feud about his influence. Dominic Cummings has been contacted for comment.