Conservative peer David Wolfson has quit as justice minister over the “scale, context and nature” of breaches of COVID regulations in Downing Street.

Lord Wolfson said in a letter to Boris Johnson he was quitting not only over the events themselves, or the prime minister’s “own conduct,” but also “the official response to what took place”.

He said: “I regret that recent disclosures lead to the inevitable conclusion that there was repeated rule-breaking, and breaches of the criminal law, in Downing Street.

“I have – again, with considerable regret – come to the conclusion that the scale, context and nature of those breaches mean that it would be inconsistent with the rule of law for that conduct to pass with constitutional impunity”.

It comes after Mr Johnson, his wife Carrie and Chancellor Rishi Sunak paid fines for attending a birthday party held for the prime minister in the Cabinet room in No 10 in June 2020.

Neither Mr Johnson nor Mr Sunak indicated they would resign over their fines.

Reacting to the news, Tobias Ellwood, chair of the Defence Select Committee, told Sky News: “This is why I want the prime minister to step forward with his plan to recognise the scale of the challenge we face, the fact that the trust has been eroded, otherwise we will get this drip-feed effect of people who no longer want to stay on the sidelines.

“Let’s have the opportunity in the near future where everybody gets to make their mark and decide one way or another whether we support the prime minister towards the next general election or it is time for change.”