Scotland Yard is urgently reviewing around 30 sex cases due to go to trial in the UK after the collapse of two rape prosecutions in the past week.
Further cases at an earlier stage in the justice process will also be examined as the force looks at every one of its sex crime investigations, where a suspect has been charged.
The trial of Liam Allan, 22, was halted at Croydon Crown Court last week, while on Tuesday another prosecution collapsed against Isaac Itiary, who was facing trial at Inner London Crown Court accused of raping a child.
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 Met is reviewing with the CPS all cases where someone has been charged and those cases are progressing towards trial," a Met spokesman said.
Around 30 cases already set for trial are being prioritised, but it is not yet known how many other cases will be affected.
The Met announced a major review of its live sex crime investigations after the CPS offered no evidence against Mr Itiary.
He was charged in July this year, but police only disclosed further "relevant material" in response to his 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."
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."
Justice minister Dominic Raab said it was "absolutely right" for the Met to carry out a review, adding: "The basic principle of British justice is at stake."
He told BBC Radio 5 Live's Emma Barnett: "The proper disclosure obligations in these two cases have not been discharged, and that is deeply worrying.
"What we need to know now is quite how widespread that is and why.
"This is not a new thing. It should be made easy by technology. It's a very basic thing why it's not happening.
"I don't want to prejudice a review which is going to be under way but I do think the CPS and the police do need to have a pretty hard long look in the mirror about this."
Prime Minister Theresa May's official spokesman said: "The two cases which came to light over the past week have obviously raised some serious issues which need to be looked at in greater detail.
"The Met is carrying out work and it's important we don't seek to prejudge those reviews."
The spokesman said the attorney general last week ordered a review to look at disclosure processes - including codes of practice, guidelines and legislation relating to sexual offences and other types of crime - which is expected to report back in 2018.
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 chairman 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."