Police forces could face fresh legal action by victims of serious crime over bungled investigations following a landmark legal ruling.

Supreme Court judges found that forces should be held liable over “seriously defective” inquiries after rejecting an appeal by the Metropolitan Police linked to the case of black cab rapist John Worboys.

Following the judgment, Deputy Commissioner Sir Craig Mackey said the force may “see a growth in this type of litigation” and that resources may have to be moved away from crimes such as fraud to deal with the fallout of the decision.

A lawyer for the relatives of the victims of serial killer Stephen Port, who are already suing the Metropolitan Police, said the ruling had “a positive bearing” on the case.

Andy Petherbridge added: “This is a very bad day for the Metropolitan Police Service, as there are likely to be many more claims from victims of violent crime, but a positive day for victims in their fight for justice.”

Giving the court’s ruling on Wednesday, Lord Kerr said: “By a majority, we have held that failures in the investigation of the crimes, provided they are sufficiently serious, will give rise to liability on the part of the police.

“There were such serious deficiencies in this case. There were, of course, both systemic and investigatory failures in the case.

“But, the important point to make is that, if the investigation is seriously defective, even if no systemic failures are present, this will be enough to render the police liable.”

The first of Worboys’ victims to make a complaint to police, known as DSD, was at court to hear the judgment.

Referring to the police, she said: “Had you done your job properly, there wouldn’t be 105 victims, there would be one. I can take the one. I can’t take the 105.”

She and another woman who was also attacked by Worboys, known as NBV, were awarded £22,250 and £19,000 respectively after the High Court ruled that the Met were liable to them for failures in its investigation. The women brought their claims under Article 3 of the Human Rights Act which relates to inhuman or degrading treatment.

John Worboys prison release
The black cab used by rapist John Worboys (Metropolitan Police/PA)

Between 2002 and 2008, Worboys, who was jailed for life in 2009, carried out more than 100 rapes and sexual assaults using alcohol and drugs to stupefy his victims.

DSD made a complaint to the Met in 2003, while NBV contacted them after she was attacked in July 2007. In NBV’s case, Worboys was quickly arrested as a suspect but released without charge, while in DSD’s case he was never identified.

Scotland Yard Deputy Commissioner Sir Craig Mackey (Metropolitan Police/PA)
Scotland Yard Deputy Commissioner Sir Craig Mackey (Metropolitan Police/PA)

In the wake of the judgement, Sir Craig said: “It’s possible we will see a growth in this type of litigation and challenges – that’s always the case.”

He went on: “There is no doubt that it will have implications for how we resource and prioritise our investigations.

“We will have to consider how we balance our resources against the need to effectively investigate certain crimes. For example, we may need to consider moving extra resources into an Article 3 investigation from other areas, such as fraud.”

Earlier this month, DSD and NBV welcomed a ruling which gave them and London Mayor Sadiq Khan the go-ahead to challenge what they describe as the Parole Board’s “irrational” decision to release Worboys.

Worboys, 60, will remain in prison pending a full High Court hearing on March 13.