Wakefield had coronavirus symptoms when the couple drove to Durham but Cummings did not,calling into question whether those exceptional circumstances existed at the time of the trip.

Cummings eventually developed symptoms and was bedridden for more than a week. Wakefield later wrote a piece for theSpectator describing the ordeal but never mentioned that they had left London for support. In the same piece,she wrote of emerging"from quarantine into the almost comical uncertainty of London lockdown".

Downing Street officials also told political journalists at the time that Cummings was off work and self-isolating"at home".

A later report said Cummings also made a second trip from London during the lockdown and was spotted near Durham on April 19,days after returning to London from his first trip. Cummings described that claim as"totally false"according to a report in the LondonTelegraph.

The scandal,revealed via a joint investigation by The Guardian andDaily Mirror,is a political danger for Johnson. The opposition and even some Tory MPs have said it shows one set of rules applies to political figures and another to the general public.

"It is intolerable that Boris’ government is losing so much political capital,"Conservative MP Steve Baker wrote on Twitter on Sunday."Dominic Cummings must go."

A senior member of the government's Scientific Advisory Group for Emergencies,Professor Neil Ferguson,resigned earlier this month after he was caught breaking the lockdown rules to meet a woman he was in a relationship with.

Many of the same ministers who blasted Ferguson rushed to defend Cummings in a volley of tweets on Saturday that threaten to undermine the country's public health messaging.

In an unprecedented defence of a government staff member by cabinet ministers,Chancellor Rishi Sunak,Health Secretary Matt Hancock,Foreign Secretary Dominic Raab,Attorney-General Suella Braverman and Cabinet Office Minister Michael Gove all said Cummings had done nothing wrong.

"Caring for your wife and child is not a crime,"Gove said.

Johnson has given Cummings his"full support"however the situation is fluid and Cummings'future is in doubt.

Acting Durham police commissioner Steve White on Saturday described Cummings'conduct as"unhelpful"and"frustrating".

"Given the whole ethos of the guidance and regulations issued from the government was to reduce the spread,regardless of the reason,by travelling to County Durham when known to be infected was unwise,"he said.

"To beat this crisis,we need to be selfless as millions have been."

Downing Street has claimed that"at no stage was Cummings or his family spoken to by the police about this matter"as was reported by The Guardian andThe Daily Mail.

But a statement from Durham police said officers were told"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,"the statement said.

"In line with national policing guidance,officers explained to the family the guidelines around self-isolation and reiterated the appropriate advice around essential travel."

The Labour opposition has called for an inquiry into the affair and said Johnson must answer details about whether he knew Cummings had moved to Durham during the lockdown.

"The lockdown rules were very clear:if you or anyone in your household was suspected of having COVID-19 you must immediately self-isolate and not leave the house,"the party said in a statement.

"However,the Prime minister’s chief adviser appears to believe that it is one rule for him and another for the British people. This will cause understandable anger for the millions of people who have sacrificed so much during this crisis."