Cheltenham MP Alex Chalk has resigned as HM Solicitor General for England and Wales.
He had been the first MP from Cheltenham to serve in Government since the 1850s.
In a letter to Boris Johnson, Mr Chalk said it was “with great sadness” he was quitting the post but added he could not “defend the indefensible”.
He wrote: “To be in government is to accept the duty to argue for difficult or even unpopular policy positions where that serves the broader national interest. But it cannot extend to defending the indefensible.
“The cumulative effect of the Owen Paterson debacle, Partygate and now the handling of the former Deputy Chief Whip’s resignation, is that public confidence in the ability of Number 10 to uphold the standards of candour expected of a British Government has irretrievably broken down. I regret that I share that judgement.
“This comes at a moment of intense challenge for our country, when trust in government can rarely have been more important. I’m afraid the time has therefore come for fresh leadership.”
Chalk was the first Minister of State to resign and was the third to resign after the Chancellor Rishi Sunak and Health Secretary Sajid Javid.