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The reports suggested Cummings was spotted by neighbours in the garden as he danced to pop group Abba.
Eyebrows were raised after the BBC’s Laura Kuenssberg tweeted that a source close to Cummings confirmed he and his wife went to his parents’ home to self-isolate - but that they did not break government guidance because he and his wife stayed in a separate building.
His apparent move north came at the same time as the UK government was instructing people to remain home, with fines in place for those contravening the rules.
There has been no official comment from No. 10. Close friends of Cummings told the PA newswire: “He isn’t remotely bothered by this story, it’s more fake news from the Guardian. There is zero chance of him resigning.”
The 48-year-old is alleged to have been present at his family home when police from Durham Constabulary turned up on March 31, following a call from someone reporting they had seen Cummings in the area.
Downing Street had previously confirmed Cummings had started displaying coronavirus symptoms “over the weekend” of March 28 and 29.
The same day as police spoke with members of Cummings’ family, his boss Johnson would be admitted to hospital with coronavirus, where he would later require treatment in intensive care.
Sir Ed Davey, acting leader of the Liberal Democrats, has called for Cummings to quit over the allegations.
“If Dominic Cummings has broken the lockdown guidelines he will have to resign, it is as simple as that,” the former energy secretary tweeted.
SNP Westminster leader Ian Blackford MP said the aide’s position was “completely untenable”.
“He must resign or be sacked,” he added.
The Labour Party has demanded a “very swift explanation” from Downing Street.
A Labour spokesman said: “If accurate, the prime minister’s chief adviser appears to have breached the lockdown rules. The government’s guidance was very clear: stay at home and no non-essential travel.
“The British people do not expect there to be one rule for them and another rule for Dominic Cummings. Number 10 needs to provide a very swift explanation for his actions.”
Durham police confirmed officers had spoken to the owners of an address in the city after reports a person had travelled there from London.
A spokesman for Durham Constabulary said: “On Tuesday March 31, our officers were made aware of reports that an individual had travelled from London to Durham and was present at an address in the city.
“Officers made contact with the owners of that address who confirmed that the individual in question was present and was self-isolating in part of the house.
“In line with national policing guidance, officers explained to the family the guidelines around self-isolation and reiterated the appropriate advice around essential travel.”