A couple who claimed to have seen Dominic Cummings on a second coronavirus lockdown trip to Durham have complained to the police watchdog.

Dave and Clare Edwards put in an official complaint to the Independent Office for Police Conduct on Wednesday about Durham Police’s inquiry into their allegations, the Mirror reports.

The couple claim they are “100% certain” they saw Boris Johnson’s chief aide while out walking in Houghall Woods near Durham the morning of Sunday April 19.

A third new witness also claims they saw Mr Cummings in the local beauty spot that morning, adding: “I would recognise him again.”

Mr Cummings has described as “false” allegations that he made a second trip to the North East, after the Mirror and Guardian revealed his first trip.

They are among four witnesses who have told a joint investigation they believe they saw Mr Cummings back in County Durham on the morning of April 19 - and the first to go public.

The Tory adviser drove 260 miles with his wife, who had symptoms, and son to self-isolate at his parents’ home on March 27 at the height of the lockdown.

During their two-week stay the family took a day-trip to Barnard Castle, 30 miles away, on April 12, which he later claimed was to test his eye-sight.

But in an extraordinary press conference in the No 10 garden, the top aide denied claims by a member of the public that he was in Durham on April 19, saying he had photos and data on his phone to prove it.

A No 10 spokesman said on Thursday: “Durham Constabulary have made clear they are not taking any further action against Mr Cummings and that by locating himself at his father’s premises he did not breach the regulations.

“The Prime Minister has said he believes Mr Cummings behaved reasonably and he considers the matter closed.”

The latest revelation puts pressure on Mr Cummings to produce the evidence that he said on May 25 proves he was in London, and not Durham, on April 19.

Clare Edwards, a nurse practitioner, and her Conservative-voting husband Dave, who works in manufacturing, reported their alleged sighting to Durham Police in May.

It came after an initial witness, who first got in touch with the Mirror on April 19, claimed that both he and his wife had spotted the PM’s top aide while walking in Houghall Woods that morning.

The man, who did not want to be named, said Mr Cummings, who was with a female companion, commented as he passed by: “Aren’t the bluebells lovely?”

Since then another new witness, who also wishes to remain anonymous, claims they saw the No 10 aide and his wife walking between the local beauty spot and the family home the same morning.

Another individual subsequently told the Guardian they believe they saw Mr Cummings on Hampstead Heath in North London – a drive of less than four hours on a quiet lockdown Sunday - later that day.

Mr Cummings denies he was in Durham on April 19 and Durham Constabulary have seen insufficient evidence to support this allegation.

They concluded he may have committed a “minor breach” of the regulations when he drove to Barnard Castle on April 12 - also his wife’s birthday - but no further action would be taken.

The couple then put in a so-called Subject Access Request to establish how the force had handled their personal information - which they hoped might reveal how their complaint was followed up.

The details, heavily redacted and marked ‘official-sensitive’, eventually arrived last week but the couple, both 59, felt they showed their claims had not been taken seriously.

They have now written to the IOPC, which oversees the police complaints system in England, asking them to look into the force’s handling of their allegation.

They wrote: “Given the high profile nature of this issue it is inconceivable that this matter has not been followed up thoroughly.

“We have no personal issue with Mr Cummings or his family, but we do feel that Durham Police’s handling of our complaint is below the standard we would expect from our local constabulary.

“We ask that the IOPC investigate whether Durham Police acted thoroughly in their investigation of this matter.”

His wife called on the PM’s senior aide to release his evidence: “It would be great to see if he could produce anything. I just want the truth to be out there.”

A Durham Constabulary spokesman said: “As outlined in our statement of May 28, Durham Constabulary carried out an investigation into this matter led by a senior detective and found insufficient evidence to support the allegation”.