A witness to an alleged lockdown breach by Boris Johnson's top aide said he has been interviewed by police, as the British Prime Minister faces pressure from within his own party over Dominic Cummings' Durham trip.

Robin Lees described having had a "thorough" chat with officers about his claim to have seen Mr Cummings and his family walking by the River Tees on Easter Sunday.

It comes as one minister quit in protest at the senior aide remaining in his Number 10 post, and dozens of Conservative MPs called for Mr Cummings to go despite Cabinet members seeking to protect the adviser.

The Guardian reported that Mr Lees was interviewed yesterday evening, after Mr Cummings gave an extraordinary Downing Street press conference.

The retired teacher, of Barnard Castle, told the newspaper: "They were very thorough, asking every detail of what I saw. They were not in uniform.

"They asked me a lot about my background. They wanted to know exactly what time it was. They wanted to know if it was a clear day and did I know what Cummings looked like."

In his televised speech yesterday, Mr Cummings said he had driven for half an hour and ended up by a riverbank on the outskirts of Barnard Castle town on Easter Sunday in a trip to test his eyesight before making the long journey back to London the following day.

Returning to the car, an elderly gentleman walking nearby appeared to recognise him, he said, adding that his wife wished the man a Happy Easter "but we had no interaction with him".

Dozens of Conservative MPs have said Mr Cummings should go despite ministers seeking to protect the controversial adviser.

British health minister Matt Hancock has said he would talk to colleagues about fines imposed on families for breaking lockdown rules, after Mr Cummings received widespread public condemnation for his lockdown travel.

Asked whether fines would be rescinded for those who had given childcare-related justifications for breaking the lockdown, Mr Hancock said the government would consider this.

"We do understand the impact and the need for making sure that children get adequate childcare. That is one of the significant concerns that we've had all the way through this," he said at the British government's daily news conference.

"I think that (it) is ... perfectly reasonable to take away that question. I'll have to talk to my Treasury colleagues before I can answer it in full," he added.

Yesterday Mr Cummings said he believed he had acted "reasonably" and within the law, and had no regrets about his actions.

Mr Johnson has said he was satisfied with his aide's version of events.

However, in a poll conducted after Mr Cummings sought to explain his actions, YouGov found 71% of people believed he had broken lockdown rules and 59% thought he should resign.

Police in England and Wales have issued more than 14,000 fines for alleged breaches of lockdown laws from 27 March to 11 May, the period that included Mr Cummings' trips, according to the National Police Chiefs' Council.

Junior minister resigns as row rumbles on

Earlier a junior minister resigned over the alleged lockdown breaches by Mr Cummings.

Douglass Ross, the under secretary of state for Scotland, said he was quitting after hearing Mr Cummings' efforts to defend his trip from London to Durham.

Mr Ross said he could not "in good faith" tell his constituents who could not care for sick relatives or say goodbye to dying ones while obeying lockdown rules that Mr Cummings acted appropriately.

This morning said that "while the intentions may have been well meaning", Mr Cummings' interpretation of the rules was "not shared by the vast majority of people".

"I have constituents who didn't get to say goodbye to loved ones; families who could not mourn together; people who didn't visit sick relatives because they followed the guidance of the government," the Tory MP for Moray wrote.

"I cannot in good faith tell them they were all wrong and one senior adviser to the government was right."

A Number 10 spokesman said Mr Johnson "regrets" Mr Ross' decision to quit the government.

The spokesman said: "The Prime Minister would like to thank Douglas Ross for his service to government and regrets his decision to stand down as Parliamentary Under Secretary of State for Scotland." 

An earlier explanation of Mr Cummings' trip to Durham would have led to less "confusion" about what happened, Michael Gove has said.

The Cabinet Office minister also told Sky News: "I think it is probably right that, if Dominic had given a full explanation of these events earlier, then some of the confusion that has arisen might not have arisen.

"But, I think, fundamentally, that now he has given an account, all of us can make our minds up, whether we are bishops or broadcasters, about the appropriateness of his actions."

He said Mr Cummings had taken medical advice around issues with his eyesight and was able to "drive safely".

Asked if Mr Cummings needed to drive to Barnard Castle before going down to London, Mr Gove replied: "I think he was wise to make sure he was comfortable before driving back down to London on the A1, an inevitably busier road, and of course it is the case it was part of the National Police Chiefs' Council's guidance that you could drive at that time to take exercise as well."

Professor Stephen Reicher, a member of the British government's advisory group on behavioural science, said the Prime Minister risks undermining a sense of community needed to cope with the pandemic.

Prof Reicher said: "One of the central messages that we gave to government, one of the central points that we made was that the way we have gotten through this pandemic to date is by acting together, by thinking in terms of 'we', of what's good for the community.

"Millions of people up and down the country have done precisely that in very difficult circumstances, agonising circumstances around their families and thought 'What is good for us as a community?'

"I think the real problem here is that not simply in what Mr Cummings did but in the messaging that the Prime Minister put out. The lesson was, forget about the 'we', it's about 'I'."

He added: "The thing that really concerned me yesterday was everything was about 'I', everything was about what it means for me, there was no consideration at all of what it means to the community.

"Now, thank God, the public at large didn't take that attitude, the public at large, as I say, made those major sacrifices, but it threatens to undermine that sense of community if a figure as prominent as Dominic Cummings and if the Prime Minister himself starts undermining that 'we' message and starts talking about 'I'," he said.