Scotland Yard has launched a major review of its sex crime investigations after the collapse of two rape cases in a week.
The force has announced every live case, where the Metropolitan Police is in discussion with the Crown Prosecution Service (CPS), will be examined.
It came after a second rape prosecution collapsed in less than a week over problems relating to the disclosure of evidence.
Both cases involved the same investigating officer, and the detective remains on full duty in the sexual offences investigation unit, the Metropolitan Police said.
The trial of Liam Allan, 22, was halted at Croydon Crown Court last week, while on Tuesday, another prosecution collapsed against Isaac Itiary.
He was facing trial at Inner London Crown Court charged with the rape of a child under 16, along with other offences, but the CPS offered no evidence.
The defendant was charged in July this year, but police only disclosed further "relevant material" in response to the defence case statement submitted on December 15.
A CPS spokesman said: "On December 17 2017, the police provided new material to the CPS, which had previously been requested, and this was reviewed.
"Prosecutors decided that there was no longer a realistic prospect of conviction and we offered no evidence against the defendant at a hearing today (December 19 2017)."
The Met announced a review of the Itiary investigation as well all other live probes by the "Child Abuse and Sexual Offences (CASO) command, where the MPS is in discussion with the CPS."
Commander Richard Smith, who oversees Met rape investigations, said: "I completely understand that this case may raise concerns about our compliance with disclosure legislation given the backdrop of the case of R v Allan last week.
"The Met is completely committed to understanding what went wrong in the case of Mr Allan and is carrying out a joint review with the CPS, the findings of which will be published.
"Rape investigations are by their nature very complex, and often hinge on the contradictory accounts of the alleged suspect and the complainant about what has taken place.
"We are reviewing all our investigations, where we are in discussion with the CPS, to assure ourselves that we are meeting our disclosure obligations in an acceptable timescale based on the volume of data that some cases involve."
The review is to "ensure that all digital evidence has been properly examined, documented and shared with the CPS to meet obligations under disclosure," police said.
A spokesman for the Met said they were unable to say, at this stage, how many cases would be affected.
Concerns have previously been raised at the most senior level of the criminal bar that disclosure failures and lack of resources will lead to miscarriages of justice.
Angela Rafferty QC, the chair of the Criminal Bar Association, suggested "unconscious bias" stops the police and the CPS "impartially and thoroughly investigating and scrutinising complaints in sexual offence cases".
"It should be remembered that it is not the job of the police or CPS to judge the truthfulness or otherwise of any allegation made," she said.
"The deluge of sexual allegations in the system is well known. If the criminal justice system is to cope and cope properly then funding must be found to ensure that there are proper investigations, a proper filtering system for cases that have no merit and a proper approach by the police and CPS to disclosure issues."