Opposition and Conservative MPs have joined members of the public in calling for Mr Cummings’ resignation for what they say is a breach of lockdown restrictions.
Away from the political row, reports that Mr Johnson’s 48-year-old aide was spotted near Barnard Castle has brought national attention to the small market town.
A reviewer called “D.Cummings” published a review on Tripadvisor to say he had a “lovely trip to Barnard Castle”.
He wrote: “I know the law says not to travel unnecessarily but I’ve got a mate in a high place so I’m not worried about adhering to the rules.
“If all else fails I’ll blame kids.”
Mr Cummings told reporters at a press conference on Monday that his eyesight had been affected by Covid-19 and his wife did not want to risk the long drive back to London so they went on a “short drive” to Barnard Castle.
“We agreed that we should go for a short drive to see if I could drive safely, we drove for roughly half an hour and ended up on the outskirts of Barnard Castle town,” said the senior aide.
“We did not visit the castle, we did not walk around the town.”
The Tripadvisor commentators poked fun at Mr Cummings’ reasons for making the trip as another person writing as “big Dominic C” suggested he had “got away with” breaching lockdown.
“Had a lovely day with my family on 12th April,” wrote big Dominic C.
“Was nice and peaceful so didn’t see many people around. Can’t think why.”
Another review written by “Classic Dom” said: “I have a very stressful job telling other people how to make the world more like the way I’d like it.
“So you can imagine how great it was to get away from it all with my family.
“Pulled a sickie at work and dashed up for a chilled out couple of weeks including wander around this place.”
Tripadvisor has now published a notice on its website to say it has temporarily suspended publishing new reviews for Barnard Castle.
The popular tourism website said: “Due to a recent event that has attracted media attention and has caused an influx of review submissions that do not describe a first-hand experience, we have temporarily suspended publishing new reviews for this listing.
“If you’ve had a firsthand experience at this property, please check back soon – we’re looking forward to receiving your review.”
Mr Johnson continued to support his key advisor during Monday’s daily press briefing after he said on Sunday that following “extensive” talks with his aide, he concluded “he followed the instincts of every father and every parent”.
The senior aide also told the press conference that he did not inform the Prime Minister before his trip to Durham and admitted “arguably this was a mistake”.
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Mr Cummings said he believed his circumstances were exceptional and that he acted “reasonably and legally” and had not offered to resign or considered it.