Video report by ITV News Political Editor Robert Peston
The Government has suffered its first resignation following allegations the prime minister's chief aide broke the coronavirus lockdown rules.
Conservative MP Douglas Ross announced he would be stepping down from his role as Scotland minister due to the Government's response to Dominic Cummings travelling 260 miles from London to Durham during the height of the lockdown.
"I am faced with people who've missed funerals, people who couldn't be with loved ones as they were being treated or sadly died," Mr Ross told ITV News, "and I can't therefore look at them in the eye and say they were wrong and Mr Cummings was right".
ITV News Political Editor Robert Peston on the impact of the row:
So far he's the first minister to resign, but several high profile Tories have called for Mr Cummings to resign.
Leader of Scottish Conservatives Jackson Carlaw and former chief whip Mark Harper have both indicated they think Mr Cummings should resign.
Of course, Tories are not the only people calling for Mr Cummings to resign, Westminster leaders of he SNP, Lib Dems, Plaid Cymru, SDLP, Green Party and Alliance Party have all written to the prime minister demanding he sack his chief advisor.
And in what is being seen as an attempt by some Tories to give the PM an "easy ride", two senior committee chairs have been excluded from grilling Boris Johnson on Wednesday at 2pm.
Foreign Affairs Committee Chair Tom Tugendhat and Defence Select Committee Chair Tobias Ellwood will not attend the House of Commons Liaison Committee, which is due to question Mr Johnson tomorrow, after reportedly being excluded by chair Bernard Jenkin.
The Liaison Committee - which usually sits three times a year - is the only committee the prime minister appears in front of and is attended by the chairs of each of the select committees.
Mr Ellwood said if he was invited to the committee, he'd have asked for an independent inquiry to be held into Mr Cummings' behaviour so that the government "focus returns to mission" of fighting coronavirus.
In a statement, Mr Ross said: "I have never met Dominic Cummings so my judgement on this matter has always been open and I accept his statement on Monday afternoon clarified the actions he took in what he felt were the best interests of his family.
"However, these were decisions many others felt were not available to them."
He added: "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.
"I cannot in good faith tell them they were all wrong and one senior advisor to the Government was right."
Former whip Mr Harper made a similar statement, saying Mr Cummings “should have offered to resign, and the Prime Minister should have accepted his resignation”.
The Forest of Dean MP said he would “expect an adviser who had damaged the credibility of the Government’s central message so badly and had become the story to consider their position”.
On a trip Mr Cummings made while in Durham, to Barnard Castle, Mr Harper said an "apology should have been made and a level of regret expressed."
"I was disappointed that Mr Cummings did neither," he added.
Mr Carlow said Mr Cummings should now consider his position after proving to be too much of a distraction in the efforts to tackle coronavirus.
“Given the furore, given the distraction this is, given the distraction of the prime minister on this issue, if I were Mr Cummings I would be considering my position.”
He said his view had “been made clear to Downing Street”.
Meanwhile, a poll revealed a majority of Britons think the prime minister's adviser should resign.
Some 59% of 1,160 adults surveyed said they believe he should quit, 27% said he should, while 14% answered “don’t know”.
Professor of Primary Care Health Science Trish Greenhalgh told ITV News that she feared Mr Cummings actions had diluted the government's cononavirus measures, predicting "an uptick" in Covid-19 deaths in mid-June as a consequence.
"Once government starts being inconsistent, once the public health messages are watered down, more and more people are going to think it simply doesn't matter," she said.
Cabinet Secretary Michael Gove defended Mr Cummings on Tuesday morning, saying: "I think anyone who heard what Dominic had to say will have a chance to reflect on the decisions that he made.
"I think reasonable people will understand why he behaved as he did but of course there will be other people who may disagree with his decisions and I understand them."
Pressure has been mounting on Boris Johnson to sack Mr Cummings despite his chief aide trying to explain his reasoning behind his trip to the family estate to self-isolate at the end of March.
Mr Cummings said he believed he acted "reasonably" and within the law after driving 260 miles from London to Durham in March.
Watch: Michael Gove defends Mr Cummings's trip to Durham
At a press conference in Number 10 Downing Street's garden, Mr Cummings said he made the trip over fears of a lack of childcare if he came too ill with Covid-19 to look after his young boy.
He also revealed concerns about his family's safety but said despite the backlash, he had "not considered" resigning.
Boris Johnson attempted to shift focus away from the row by announcing all shops across England will be able to open from June 15 if they can meet the coronavirus guidelines to protect shoppers and workers.
Opposition leaders will hold talks on Tuesday morning to discuss public health messaging amid the row.
Coronavirus: Everything you need to know