Dominic Cummings says he “obviously” will not be quitting as the prime minister’s chief adviser over claims he broke coronavirus lockdown rules.
He said he did the “right thing” by travelling 260 miles with his family to be near relatives when his wife developed Covid-19 symptoms.
Downing Street said he wanted to ensure he had childcare if he got symptoms.
Labour and the SNP say he flouted the government’s own advice and are calling for an urgent inquiry into his conduct.
It comes as the government announced 282 more people had died with coronavirus since Friday, across all settings, bringing the total to 36,675.
Mr Cummings told reporters he “behaved reasonably and legally” when asked about the trip from London to Durham.
Asked whether it looked good, he said: “Who cares about good looks? It’s a question of doing the right thing. It’s not about what you guys think.”
He was later asked by reporters whether he would consider his position, he said: “Obviously not.”
“You guys are probably all about as right about that as you were about Brexit: do you remember how right you all were about that,” he added.
Mr Cummings masterminded the 2016 Vote Leave campaign before being made Prime Minister Boris Johnson’s chief political adviser.
Transport Secretary Grant Shapps said the prime minster – who has not commented so far – had “full confidence” in Mr Cummings, following calls from the SNP and the Scottish Labour Party for him to quit or be fired.
Police said they attended a property in County Durham, after the Guardian and the Daily Mirror newspapers first reported Mr Cummings had been seen near his parents’ home in early April.
Durham Police and Crime Commissioner Steve White said it had been “most unwise” for Mr Cummings to make the journey, “given the whole ethos” of the government’s guidance.
Speaking at the daily coronavirus briefing, Mr Shapps said Mr Cummings went to Durham because “that’s where the family was”.
“As we all do in moments of crisis, we always seek to have our family, those who can assist us, around us and I think that’s all that has happened in this case.”
He said he did not know the “personal circumstances” of the Cummings family that prevented them seeking help closer to home.
Quizzed about how this fitted with the government’s guidance, which is to stay at home, he said: “The important thing is that everyone remains in the same place whilst they are on lockdown.”
He added: “The guidance says if you’re living with children keep following this advice to the best of your ability.
“However, we are aware that not all these measures will be possible depending therefore on circumstances.”
He said it was “for an individual to make the decision” on how best to practice lockdown measures.__BBC