During a press conference at Downing Street today, Mr Cummings says he travelled to his parents’ farm in County Durham with his wife and four-year-old son because they were in an “exceptional” situation of having no suitable childcare available in London if they both became seriously ill.

He also confirmed he drove to the outskirts of Barnard Castle village, about a half hour’s drive away, to make sure he was fit to drive before heading back down to London for work after self-isolating for 14 days.

Mr Cummings said: “I don't regret what I did. I think reasonable people may well disagree about how I thought about what to do in the circumstances, but I think what I did was actually reasonable in these circumstances.

Dominic Cummings, senior aide to Prime Minister Boris Johnson, answers questions from the media after making a statement at 10 Downing Street

"The rules made clear that if you are dealing with small children that can be exceptional circumstances.

"And I think that the situation that I was in was exceptional circumstances and the way that I dealt with it was the least risk to everybody concerned if my wife and I had both been unable to look after our four-year-old.”

Mr Cummings also revealed that his son was taken to hospital after falling ill while staying at his parents’ farm, and that he drove to pick him up the next day as there were no taxis available at the time.

During his briefing on Sunday, Boris Johnson insisted his adviser acted legally and within the guidelines - but critics say the UK Government's lockdown message has been undermined.

Dominic Cummings during his Downing Street press conference on Monday.

SNP step up calls for probe and sacking of Dominic Cummings

The former Vote Leave boss has been under fire since the Guardian and Daily Mirror reported he was seen in County Durham at his family's farm during lockdown.

It later emerged he had travelled there from London with his son and wife, who had developed symptoms of the virus, so that he could self-isolate close to relatives who could take care of their child if necessary.

He said today that his sister and nieces, who were in a separate property 50 metres away, were in a position to be able to do that if it became necessary.

Mr Cummings added: “Obviously we kept very, very far away from them (my parents). There are various reports that I visited them, I was staying with them. That's all completely untrue.”

He also revealed he did not ask the Prime Minister about the decision to travel north because he himself was ill and had “huge problems to deal with.”

Mr Cummings said he arrived at his parents’ house on March 27th at about midnight and awoke in bed feeling ill the next day. He said his wife’s condition began to improve as his own situation worsened.

He says his child started vomiting and that they called 999 and went to hospital. Mr Cummings said he drove about three or four miles to the hospital and picked them up and returned to the farm and did not make contact with anyone else during this time.

He said that, during his recovery, he walked to some nearby woods with his wife and child and that some people saw them from a distance, but he stressed they were still on private land at the time.

He says he sought expert advice about returning to work 15 days after his symptoms started.

Mr Cummings says he and his family went for a drive to Barnard Castle to make sure he was safe to drive back to London, as his eyesight had not been great when he was battling illness in the days before. He says he walked around and, on the drive back, pulled over as his child needed a toilet stop and that they saw some some people but maintained a social distance.

He said it was “reasonable” to make this separate journey and believes this was the right decision.

Mr Cummings was photographed back at Downing Street on April 14th but, according to The Observer and Mirror, he was seen again by an unnamed witness in Durham on April 19th.

Mr Cummings denies making any further trips after returning to London on the night of April 13th.

Police have also been formally asked to review the information surrounding Mr Cummings' visit to the area.

Mr Cummings said he could understand why people believe he should have stayed in London but he “respectfully disagrees” and said the legal rules do not cover all circumstances and rules regarding small children in “extreme circumstances.”

In response to questions from the media, he said: "No, I have not offered to resign. I have not considered it. I think it's reasonable to say that other people would have behaved differently, in different ways, in this whole situation. But as I stress I was trying to balance lots of competing things."

"I think what I did was actually reasonable in these circumstances. The rules made clear that if you are dealing with small children, that can be exceptional circumstances."

"I am here to do the best I can for the government and change the country for the better."

'I don't regret what I did' - Dominic Cummings explains his actions during lockdown