Scotland Yard has "unreservedly apologised" to the victims of black cab rapist John Worboys after it lost an appeal at the Supreme Court.
The two women, who were sexually assaulted in 2003 and 2007 and cannot be identified for legal reasons, won compensation for the police's failure to investigate the crimes.
The Supreme Court unanimously dismissed The Metropolitan Police's appeal.
One of the first victims, referred to as DSD, was attacked in 2003, but Worboys was never identified as a suspect.
In the case of a second victim, known as NBV, who was attacked in 2007, Worboys was arrested but released without charge.
The 60-year-old serial sex attacker was arrested a year later and jailed indefinitely in 2009, with a minimum term of eight years, for drugging and sexually assaulting his female passengers.
He was convicted of 19 counts of sexual assault against 12 women, however the true number of victims could be more than 100, with confirmed victims in Chelsea and the West End.
The women are also pursuing a judicial review of the Parole Board's decision to release Worboys.
Deputy Commissioner of the Metropolitan Police, Sir Craig Mackey, said the Met fully accepts the decision of the court.
"We have always accepted that serious mistakes were made in this investigation and it was only the courage of the victims coming forward, including these two claimants, that enabled us to finally convict Worboys.
"We know we should have done more in the initial investigation and today, as we did following his conviction, I unreservedly apologise to the victims we failed."
Speaking about the appeal, Mr Mackey, continued: "The MPS appealed, and this was supported by the Government, because police forces needed absolute clarity on the boundaries of police responsibility and liability for their investigations.
"We have always been clear that the appeal to the Supreme Court was not based on factual differences between us and the victims, but on the appropriate interpretation of European human rights law.
"This appeal did not seek to recover the compensation and costs awarded to the claimants. Furthermore, the MPS agreed from the outset of the proceedings to pay the legal costs of the claimants whatever the outcome of the appeal – it was important that the issues could be examined through the courts without any financial risk to the claimants."
In his closing statement, he said: "The MPS and other forces will now consider the full implications of the judgement and what it means for investigations in the future.
"There is no doubt that it will have implications for how we resource and prioritise our investigations."
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