Read Munira Mirza’s resignation letter to Boris Johnson in full

Four key members of No 10 staff, including Ms Mirza, quit roles on Thursday

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

Boris Johnson’s leadership was plunged into further turmoil today after the resignation of one of his longstanding advisers.

Munira Mirza, No10s head of policy and a known Johnson loyalist, quit over his use of a smear against Sir Keir Starmer, in which he incorrectly claimed the Labour leader was responsible for the failure to prosecute paedophile Jimmy Savile during his time as director of public prosecutions.

In her resignation letter Ms Mirza said it was “desperately sad” the prime minister had let himself down with a “scurrilous accusation” aimed at Sir Keir.

Just hours later Jack Doyle, No 10’s director of communications, chief of staff Dan Rosenfield and principal private secretary Martin Reynolds all also resigned, although their departures are not thought to be linked to Ms Mirza’s.

Here is Ms Mirza’s letter of resignation to the PM in full:

Dear Prime Minister,

It is with great regret that I am writing to resign as your Head of Policy.

You are aware of the reason for my decision: I believe it was wrong for you to imply this week that Keir Starmer was personally responsible for allowing Jimmy Savile to escape justice. There was no fair or reasonable basis for that assertion. This was not the normal cut-and-thrust of politics; it was an inappropriate and partisan reference to a horrendous case of child sex abuse. You tried to clarify your position today but, despite my urging, you did not apologise for the misleading impression you gave.

I have served you for fourteen years and it has been a privilege to do so. You have achieved many important things both as Prime Minister and, before that, as Mayor of London. You are a man of extraordinary abilities with a unique talent for connecting with people.

You are a better man than many of your detractors will ever understand which is why it is desperately sad that you let yourself down by making a scurrilous accusation against the Leader of the Opposition.

Even now, I hope you find it in yourself to apologise for a grave error of judgement made under huge pressure. I appreciate that our political culture is not forgiving when people say sorry, but regardless, it is the right thing to do. It is not too late for you but, I’m sorry to say, it is too late for me.

Yours sincerely,

Munira