Boris Johnson's head of policy has resigned over his remarks to Sir Keir Starmer, claiming that he failed to prosecute serial sex offender Jimmy Savile when he was director of public prosecutions.

Munira Mirza, Director of the Number 10 Policy Unit, has resigned stating that Mr Johnson should have apologised for the remarks made during a Commons debate on Monday, January 31. 

In her resignation letter, published by The Spectator, she wrote: "You are a better man than many of your detractors will ever understand, which is why it is so desperately sad that you let yourself down by making a scurrilous accusation against the leader of the opposition."

On Thursday, February 3 the PM backed down stating he understood Sir Keir "had nothing to do personally with those decisions."

York Press: Prime Minister Boris Johnson during a visit to Talbot Gateway in Blackpool on February 3 (PA)Prime Minister Boris Johnson during a visit to Talbot Gateway in Blackpool on February 3 (PA)

Speaking to broadcasters, the Prime Minister said: “I want to be very clear about this because a lot of people have got very hot under the collar, and I understand why.

“Let’s be absolutely clear, I’m talking not about the Leader of the Opposition’s personal record when he was DPP and I totally understand that he had nothing to do personally with those decisions.

“I was making a point about his responsibility for the organisation as a whole.

“I really do want to clarify that because it is important.”

Downing Street has confirmed that Conservative MP Andrew Griffith has been made the head of the Prime Minister’s policy unit.