Munira Mirza’s resignation suggests the game is up for Boris Johnson

The departure of the head of his policy unit is another serious blow for the prime minister, writes John Rentoul

Boris Johnson walking out of Downing Street with Munira Mirza (PA)

She may be unknown to most voters, but Munira Mirza’s resignation yesterday was the breaking of another pit-prop under Boris Johnson’s creaking premiership. She was head of the policy unit and didn’t organise or attend any of the lockdown-breaking gatherings, so she wasn’t part of the clearout of No 10 that the prime minister had already promised.

Johnson tried to make it look as if she was, by bringing forward the announcement of the departures of Jack Doyle, Dan Rosenfield and Martin Reynolds, three officials who had already been selected to carry the can for gardengate, as the scandal should really be called.

Her departure was different. It exposed what a mistake it was for Johnson to “imply this week that Keir Starmer was personally responsible for allowing Jimmy Savile to escape justice”, as Mirza put it in her resignation letter. The prime minister had discussed using Starmer’s record as director of public prosecutions in his response to Sue Gray’s update on her gardengate investigation on Monday. Mirza, supported by others, strongly advised against it, but Johnson went ahead with it anyway.