Dominic Cummings has said he should have resigned or admitted he had taken a trip to Barnard Castle during lockdown.
The PM’s former chief adviser said he did not ignore the rules during his trip to Durham but said should have come clean.
He claimed there were ‘security problems’ at his home which forced him to take his family up to his parents’ home.
But he conceded the way No 10 handled the fallout was ‘completely wrong’ and admitted he should have resigned.
His comments came during a brutal hour-long attack on the Prime Minister, his wife Carrie and the government’s Covid response.
He sat down with the BBC’s Laura Kuenssberg as he unleashed his fury on his former office, which he left last year amid a power struggle.
The PM’s former chief adviser said he did not ignore the rules during his trip to Durham but said should have come clean
Speaking about Barnard Castle he was pushed on whether he had told the truth during a press conference he gave in Downing Street’s Rose Garden.
Mr Cummings was the subject of ridicule last year after claiming he took his family on a 30-mile journey to the castle in Durham to ‘test his eyesight’.
He said: ‘Everything I said in the Rose Garden was true but I didn’t go into all the security concerns and the background no.
‘There’s absolutely no doubt that the way we handled the whole thing was wrong on the Monday.
‘What I should have done is either just resigned and said nothing about anything or I should have spoken to my family and said listen we’re just going to have to come clean about the whole thing.’
On the eye test claims, he added: ‘The country was in a terrible situation, the Prime Minister nearly died. It may seem odd but at the time it didn’t seem odd at all.
‘If you’re going to drive 300 miles to London tomorrow, go and drive up and down the road now and see how you feel about the whole thing.
‘It was just about seeing if I was okay. If you can’t drive 30 miles you know you’re not going to be able to drive 300 miles the next day. It was as simple as that.
‘I understand that people were upset but I did not ignore the rules, I had been discussing security problems with cabinet officials for months. It was reasonable to move regardless of the coronavirus situation.’
In an interview with the BBC, he said by the middle of January 2020 – even before Covid struck, the Prime Minister ‘did not have a plan for governing’
Elsewhere in the interview he admitted he thought Boris Johnson being Prime Minister was ‘terrible for the country’, but he and ‘a few dozen’ backers sought to use his premiership to their advantage.
The former de facto chief of staff in No 10 said he had found Mr Johnson to have ‘hopeless’ traits after working with him during the 2016 Brexit referendum, but agreed after he entered Downing Street three years later to assist him.
But Mr Cummings, who left No 10 in the autumn after a power struggle, admitted he was now working to hasten the Prime Minister’s demise.
Asked during a BBC interview aired on Tuesday whether he was looking to ‘hasten’ Mr Johnson’s departure from Downing Street, he said: ‘Certainly. The sooner he goes the better, for sure.’
In the hour-long broadcast, Mr Cummings said he had looked to ‘exploit’ the situation the country found itself in after Mr Johnson took power.
Mr Cummings, asked whether he had agreed to work with Mr Johnson so he could ‘get him to do what you wanted’, replied: ‘In part, yes. He didn’t know what he was doing but he did know that he needed help.’
The Vote Leave mastermind added: ‘I think it is terrible for the country but I keep trying to stress, you’ve got to balance up the different possibilities.
And he admitted that he and the rest of his Vote Leave allies began to clash with the then Carrie Symonds over who controlled the premier.
‘From a practical matter, all our options were bad, so it was, which is the least bad option? The least bad option seemed to be, exploit the current situation to try and push certain things through and get the country into a better position.’
Asked who was behind the decision to back Mr Johnson on the premise of securing Brexit, he replied: ‘Me and a network of people – some of us who did the Vote Leave campaign, some of us who did other things. A few dozen maybe.’
Mr Cummings also revealed that he considered a coup against Mr Johnson only ‘days’ after the 2019 poll – during which he had helped him secure one of the largest general election wins in decades – due to fears the Conservative Party leader’s then-girlfriend, Carrie Johnson, was trying to oust Vote Leave personnel.
‘Before even mid-January we were having meetings in Number 10 saying it’s clear that Carrie (Johnson) wants rid of all of us,’ he said.
‘At that point we were already saying by the summer either we’ll all have gone from here or we’ll be in the process of trying to get rid of him and get someone else in as prime minister.’
He said there was a ‘big argument’ after Mrs Johnson, a former Tory head of communications, was looking to appoint and fire people ‘in ways that I thought were unethical and unprofessional’.
The 49-year-old accused Mr Johnson of not having a plan for office and said he ‘doesn’t know how to be Prime Minister’, claiming his ‘only agenda’ to be ‘buy more trains, buy more buses, have more bikes and build the world’s most stupid tunnel to Ireland – that’s it’.