Dame Cressida’s shock resignation came in the wake of a damning report by the Independent Office for Police Conduct (IOCP) which revealed how officers based at Charing Cross had shared vile social media messages in which they had joked about rape and killing black children.

Mr Khan demanded the Commissioner come up with an urgent plan to root out racism, misogyny and homophobia in the force and also to restore damaged public confidence.

But after receiving the plan, the Mayor let it be known he was unhappy with the proposals and Dame Cressida resigned.

Addressing the London Assembly, Sir Stephen said the content of the messages could not have come as a surprise to the Mayor because the IOPC investigation had been taking place for four years.

He told the committee: “The text messages and the Charing Cross case cannot have been a surprise to this mayor, Mopac (the Mayor’s Office for Policing and Crime) have been briefed on these events and they have been under investigation for four years.

“Only a few weeks ago, the mayor was a vocal supporter of the commissioner in a tripartite meeting with the Home Secretary. Hence my surprise at what’s happened.

He added: “I feel sad for my boss that her police career and lifetime of public services ended in this way. I know that I’m not alone in feeling this.”

Sir Stephen said when the Commissioner had sought feedback from the Mayor about her proposals and how she might improve the plan, she had been “stonewalled”.