The Mayor of London and a former police watchdog remain at loggerheads over claims that Britain’s most senior police officer was forced out of her job.

Sir Thomas Winsor and Sadiq Khan went head to head in front of the London Assembly Police and Crime Committee on Wednesday to be questioned about the departure of Dame Cressida Dick earlier this year.

A report by Sir Thomas found she had been intimidated into leaving but Mr Khan began by telling the committee that the investigation was biased – a claim dismissed by the former inspectorate of constabulary as “absurd”.

Dame Cressida quit in the early evening of February 10 this year despite giving a media interview that morning that she had no intention of resigning.

The committee heard that pressure had mounted on her to resign throughout the day, with Mr Khan having told her at one earlier meeting “one or other of us is going to end up being substituted”.

It is claimed that during one phone call Mr Khan’s chief of staff David Bellamy told Dame Cressida that should she resign in April, at the end of her existing contract, the mayor would publicly emphasise all she had achieved in her job.

He also suggested she would receive six months’ pay, but no more.

Sir Thomas said this was “part of the pressure that was being applied to the commissioner to persuade her to resign without invoking the statutory process”.

He said that if the Mayor had followed official processes to seek Dame Cressida’s removal, he should have given the then-commissioner notice in writing of his grounds for seeking her removal from her job.

He also said Mr Khan should have written to the Inspectorate of Constabulary to ask for their opinion, have given the commissioner a hearing and asked for the approval of the Home Secretary, but did none of those things, Sir Thomas said.

Mr Khan maintains that he went above what was required of him by law.

The Mayor has also been accused of unlawful conduct over allegedly pressuring Dame Cressida to sack officers who had been allowed to continue serving after a messages scandal.

During a meeting on February 2 this year, Mr Khan had urged Dame Cressida to get legal advice about officers who had been based at Charing Cross and had shared deeply offensive messages, but were still serving in the force.

Sir Thomas said that Mr Khan had suggested Dame Cressida take the same action that Ed Balls did in the wake of the Baby P case, after which he sacked Haringey Council’s head of children’s services Sharon Shoesmith, despite her later receiving a payout for unfair dismissal.

He said the Mayor’s actions “could and in my view do amount to unlawful conduct”. The commissioner did not have the power to sack the officers.

Mr Khan maintains that he advised the commissioner to get independent legal advice to see what options were available to deal with the officers and whether the correct decisions about discipline had been made.

During awkward exchanges, the mayor repeatedly listed scandals that have beset the Met in recent years, including the murder of Sarah Everard, the stop and search of British athlete Bianca Williams, the strip search of teenager Child Q at school and failings around the unsolved murder of Daniel Morgan and serial killer Stephen Port.

Sir Thomas said most of those events happened before Mr Khan asked the Home Secretary to give Dame Cressida a three-year extension to her contract, rather than the two years she was granted in September 2021.

He told the committee for Mr Khan “to reel off these other terrible things is frankly beside the point”.

At one point, committee chair Susan Hall asked the Mayor if he was “running down the clock” by listing the scandals and also told him “your attitude towards Sir Tom has been quite appalling … totally unbecoming of a mayor, let me tell you”.