Dominic Cummings’ actions have made a “mockery” of police enforcement of lockdown measures, a police and crime commissioner has said.

Mr Cummings travelled to County Durham in March to self-isolate with his family – apparently because he feared that he and his wife would be left unable to care for their son – while official guidelines warned against long-distance journeys.

Further reports suggested he took a second trip to the North East in April, having already returned to London following his recovery from Covid-19.

Prime Minister Boris Johnson has thrown his support behind his aide and said he acted “responsibly, legally and with integrity”.

But Gloucestershire’s independent police and crime commissioner Martin Surl told BBC Radio 4’s Today programme on Monday that Mr Cummings’ actions will make it much harder to enforce lockdown restrictions.

He added: “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.

“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.”

Durham’s former chief constable Mike Barton said the people who make the rules cannot break them or there will be “chaos”.

Speaking on BBC Breakfast, Mr Barton added: “Policing the lockdown has probably been one of the toughest assignments ever given to the British police and they have risen to the challenge.

“But what the Prime Minister did yesterday has now made it exponentially tougher for all those people on the front line, those PCSOs (police community support officers) and cops on the front line, enforcing the lockdown.

“We are in the middle of a national emergency and people who make the rules cannot break the rules, otherwise we are going to have chaos.”

We have got here really selfish acts that are undermining the efforts of the British public and British police to make us all safe, and if an inquiry by Durham Constabulary would assist us with that then I would commend it

Asked if officers should go through “hours and hours” of CCTV footage to find out if the trips were made, he said it was a matter for the force, but added: “If I thought that the entire edifice of Durham Constabulary was at risk I would make sure we got to the truth.

“If you’re going to expend hundreds of hours and that’s going to put other people at risk then you wouldn’t do it.

“We have got here really selfish acts that are undermining the efforts of the British public and British police to make us all safe, and if an inquiry by Durham Constabulary would assist us with that then I would commend it.”