A British police officer who admitted 24 counts of rape against 12 women and a string of sex offences over two decades was formally sacked on Tuesday.

Metropolitan Police Assistant Commissioner Louisa Rolfe said David Carrick's case was "sickening and horrific" and had "far-reaching consequences" for policing.

"I truly hope to never see its like again," she told an internal disciplinary hearing, which was brought forward after Carrick's admissions in court.

Carrick, 48, had been suspended from his job in an armed unit protecting MPs and foreign diplomats since the allegations came to light in late 2021.

Police misconduct hearings are typically held after the conclusion of criminal proceedings against an officer. 

But Carrick's was fast-tracked after his guilty pleas on Monday and, unusually, opened to the media given the widespread concern about his crimes.

Lawyer Hywel Jenkins, representing Met Police Commissioner Mark Rowley, called Carrick's crimes "heinous, targeted and deliberate".

They have had a "catastrophic" impact on his victims and their families, while also undermining confidence in the police service, he added.

"The public of Greater London expect police officers to uphold the law and protect women from violence," said Rolfe. 

"PC (police constable) Carrick did the opposite."

Carrick, a former soldier who did not attend the hearing and had no legal representation, was sacked for gross misconduct.

He will be sentenced in court over two days from February 6.

His offending has heaped pressure on Rowley, who only took over as head of Britain's biggest police force, in September last year.

Public trust in the Met had already suffered from the conviction of another officer for the kidnap, rape and murder of a young woman two years ago.

Wayne Couzens, who killed Sarah Everard in 2021 and is currently serving a whole-life sentence, also served in the same unit as Carrick.

But in both cases, vetting procedures that could have identified their offenders earlier were found wanting.

No action was taken either against Couzens over allegations in 2015 that he exposed himself or Carrick, who had a string of claims against him.

Two official reports into the Met and other forces in England and Wales concluded background checks were lax and there was a culture of impunity.

Rowley has pledged to "go after the racists and misogynists who are undermining us", leading to a wave of disciplinary action against officers. 

More than 1,600 claims of sex offences and domestic violence against just over 1,000 Met Police officers and staff are currently under review.