BORIS JOHNSON’s government was rocked this morning by a ministerial resignation over the Prime Minister’s senior adviser Dominic Cummings’s conduct during the coronavirus lockdown.

Scotland parliamentary under-secretary Douglas Ross said that he was quitting after hearing Mr Cummings’s statement on Monday, in which he defended his 260-mile road trip from London to Durham while the nation was told not to travel.

Mr Cummings said that he and his wife, journalist Mary Wakefield, both felt ill from suspected Covid-19 and had driven with their son to Durham on March 27 to stay on his father’s farm.

He said that he made the trip in case he needed his sister or nieces to look after his son. The  four-year-old was later admitted to hospital, accompanied in the ambulance by his mother, he claimed. 

He did not apologise and said that he did not regret his actions.

Mr Cummings also said that on April 12 he and his wife drove from Durham to the outskirts of the town of Barnard Castle to” test his eyesight” before they returned to London.

Experts from the Royal College of Ophthalmologists and Moorfields Eye Hospital have since said there was little evidence to link Covid-19 to eyesight problems.

Mr Ross said that he would not be able to back the government over Mr Cummings’s actions while his constituents were prevented from being with their sick and dying loved ones during the coronavirus outbreak.

He added: “I cannot in good faith tell them they were all wrong and one senior adviser to the government was right.”

But Cabinet Office Minister Michael Gove claimed that Mr Cummings acted in an “entirely reasonable” way and within the law, adding that he was “wise” to test his eyesight.

Mr Johnson said that his aide acted “legally and with integrity.”

But Communities Secretary Robert Jenrick said he could not rule out the possibility of further ministerial resignations.

Tory chairman of the Commons public administration & constitutional affairs committee William Wragg said it was “humiliating” to see ministers defending Mr Cummings.

Former chief whip Mark Harper said that Mr Cummings “should have offered to resign, and the Prime Minister should have accepted his resignation.”

Veteran Conservative MP Sir Roger Gale said that the back-bench 1922 committee should press Mr Johnson to sack Mr Cummings.

The PM’s personal approval rating has dropped by 20 points in four days to 1 per cent following his defence of Mr Cummings, according to polling from Savanta ComRes.