An assistant Metropolitan Police commissioner has said she is “truly sorry” after the force let down the victims of sacked PC David Carrick who has been unmasked as one of the country’s most prolific sex offenders.

Speaking on the eve of Carrick’s sentencing on 49 criminal charges including rape, Assistant Commissioner Barbara Gray said: “He should not have been a police officer.”

Carrick, 48, served as a Met officer for 20 years. He was sacked from the force for gross misconduct after admitting 49 criminal charges – including 24 counts of rape against 12 women over an 18-year period.

We let them down and we failed to identify a man in the ranks of the Metropolitan Police Service who carried out the most awful offences

Ahead of his two-day sentencing hearing at London’s Southwark Crown Court, Assistant Commissioner Gray, the Met’s lead for professionalism, said: “I am truly sorry for the harm and devastation he has caused them.

“We let them down and we failed to identify a man in the ranks of the Metropolitan Police Service who carried out the most awful offences.

“He should not have been a police officer.”

She also warned: “More detail will be provided about the cruel and abusive nature of his crimes and about the impact they have had on the tremendously brave women who came forward to provide evidence against him.”

Carrick has admitted to “the most appalling offences against women” and this sentencing period needs to be about his victims as “they truly deserve to have their voices heard and see justice done”.

She added that the Met is “determined to root out those who corrupt our integrity”.

The harsh spotlight thrown up by Carrick’s crimes has seen the Met speak out about its “genuine and urgent commitment to address the systemic failings” within the force, she added.

These have been identified by the Metropolitan Police’s own reviews and by His Majesty’s Inspectorate and Baroness Casey.

Last month, Metropolitan Police Commissioner Sir Mark Rowley said that two or three police officers are expected to appear in court each week to face criminal charges in the coming months as the scandal-hit force attempts to reform.

He told the London Assembly Police and Crime Committee on Wednesday that more “painful stories” will emerge as moves progress to remove hundreds of corrupt officers who are thought to be serving.

After Carrick’s guilty plea nearly three weeks ago, Home Secretary Suella Braverman said more disturbing cases involving police officers could be uncovered in the short term.

A new Met Police integrity hotline has received “tens of calls” a week, leading to new investigations, Sir Mark said, a third of which relate to other forces.

In the wake of Carrick’s conviction, around 1,000 previous cases involving Met officers and staff who were accused of sexual offences or domestic violence are being reviewed to make sure they were handled correctly.

This is expected to be completed by the end of March.

Sir Mark told the Assembly that as well as these, in the coming weeks and months he expects two or three officers per week to appear in court charged with offences linked to dishonesty, sexual offences, violence or domestic violence.

Sir Mark has spoken of his commitment win the trust of Londoners by delivering high standards in the police.

Efforts to try to make this happen include investing millions of pounds and increasing the resources in the Directorate of Professional Standards.

The aim is to identify and investigate wrongdoing and more officers with specialist skills and experience have been brought on board to do this work.

The Met also said that a dedicated domestic abuse and sexual offending investigation team has been set up with more than 50 experienced investigators targeting any officer or staff member who may be engaged in domestic abuse or sexual offences.

There is also a new anti-corruption and abuse command which is proactively investigating and identifying officers and staff who abuse their positions of trust whether on duty or off duty, in person or online.

The Met also says that a thorough audit of national police systems, specifically the Police National Computer and Police National Database, is being undertaken to seek out intelligence and information about officers and staff that may not be known by the organisation.

All closed cases from the past decade where officers and staff were reported to the Directorate of Professional Standards for involvement in incidents ranging from using inappropriate language in the workplace to allegations of the most serious sexual offending are being reviewed.

The Met said it expects most cases should have been dealt with appropriately but it knows it has previously failed to identify patterns of behaviour and consider prior offending or incidents.