Mayor of London Sadiq Khan has denied reports he issued an ultimatum to outgoing commissioner Dame Cressida Dick demanding she dismiss officers involved in the Charing Cross case or face suspension herself.

Officers at the London police station were revealed to have sent racist and misogynistic messages to one another by a police misconduct report published earlier this year.

The Times had reported that Dame Cressida told senior colleagues that Mr Khan had made the ultimatum to her.

Speaking to LBC, Mr Khan said: “Some of that is accurate. I was angered and disgusted by what a number of Metropolitan Police officers – serving officers – said.

“I was concerned about the impact on trust and confidence. It is not the case that the commissioner was given an ultimatum to sack them or she would be sacked.”

Mr Khan also said a Metropolitan Police Twitter account had shared information about him that was “misleading”.

On Thursday, the verified Met Police Taskforce Twitter account retweeted a tweet which read: “If the Mayor of London doesn’t understand that the process for sacking officers is independent of chief constables … well that’s a bit of a problem.”

The Met Police account quote-tweeted the original and added the words “Exactly this”.

The tweet has since been deleted and was described as “unacceptable” by a Met spokesman.

Mr Khan told LBC: “When you have Met Police accounts amplifying information that is misleading, how is it possible for officers concerned about behaviour or other officers to come forward?

“Why are we surprised when whistle-blowers don’t come forward if this is the attitude both the IOPC talked about and you’ve exemplified in relation to a blue-ticked account?”

The Mayor of London said the Met Police has “deep cultural issues”, including “overt racism, sexism, misogyny, homophobia, discrimination”.

He suggested on LBC that there had been improvements at the Met Police since he was a child, saying: “There are so many decent dedicated, brave officers. But there has got to be an acknowledgement that there are deep cultural issues.

“We are not talking about unconscious bias, we’re not talking about unwitting prejudice. We’re talking about overt racism, sexism, misogyny, homophobia, discrimination and the like.”

He said victims of serious crimes including rape, sexual abuse and knife crime “are not coming forward because they don’t trust the police”. He said witnesses are also not coming forward in some cases.

Elsewhere, Mr Khan said he would not back the Home Secretary’s choice for the next Met Police Commissioner if he does not have confidence in them to do the job.

The Mayor of London said: “One of the things I have got to say to Londoners is I will not support the appointment of the next commissioner if I don’t have confidence that he or she understands the importance of addressing these deep cultural issues.”

Home Secretary Priti Patel is ultimately responsible for appointing the most senior officer of the Metropolitan Police.

“The legislation is quite clear that the Home Secretary appoints the commissioner,” he said.

“The good news is that legislation also says ‘with due regard to the Mayor of London’.

“I have got no doubt the Home Secretary will be incredibly professional when it comes to recruiting the next commissioner.”

Commenting on the tweet by the Met Police Taskforce, a spokesman for the Metropolitan Police said: “This tweet was unacceptable and shouldn’t have been shared from a Metropolitan Police account.

“Senior officers are addressing the matter and will be reminding officers that they are expected to be independent and impartial at all times, on and off duty, including on social media.”