The Metropolitan Police has identified more than 4,000 grooming gang cases that may need to be reinvestigated, according to a report.Scotland Yard has been carrying out a major audit of group-based sexual abuse in London dating back to 2010, amid concern that perpetrators could still be at large.Of the more than 12,000 alleged incidents that were reported to the Met during the period, a review has found that a third of them may need to be reopened.The potential major escalation of the Met's policing of historic grooming gang cases comes despite Sir Sadiq Khan, the Mayor of London, previously claiming there was 'no indication' grooming gangs were operating in the capital.In a January 2025 video clip, he was filmed repeatedly refusing to discuss the scale of the problem when he appeared before the London Assembly during a police and crime committee meeting.Susan Hall, the Conservative leader on the Greater London Authority (GLA), asked Sir Sadiq about how many rape gangs were in London, only for him to ask her seven times what she meant.The response led to criticism from the Conservatives and Reform, alongside accusations of a cover-up and claims from victims that the mayor was 'gaslighting them'. The Mayor of London has repeatedly denied that his city was blighted by the kinds of child abuse seen in towns such as Rochdale and Rotherham. The potential major escalation of the Met's policing of historic grooming gang cases comes despite Sir Sadiq Khan previously claiming there was 'no indication' grooming gangs were operating in the capital The Met commissioner, Sir Mark Rowley, has warned that he will need more resources and officers to deal with all the cases which are now being looked at again He has previously refused to use the term 'grooming gang', which some say has hindered efforts to support victims.But last June Baroness Casey published a review of the response to grooming gangs, concluding the criminal justice system had been letting down victims for decades.The report found the gangs were far more widespread, organised and underreported than the Mayor previously admitted. The report also found local authorities and other official bodies had shied away from tackling 'ethnicity or cultural factors' in grooming gangs 'for fear of appearing racist'. Her findings prompted Prime Minister Sir Keir Starmer to order the creation of a national inquiry, with former England children's commissioner Baroness Anne Longfield announced as its chair last December. The report also led to the National Crime Agency (NCA), known as Britain's FBI, setting up Operation Beaconport to identify criminal cases that had been closed prematurely.Police forces nationwide were asked to look again at reports they had received of sexual abuse in which there was more than one alleged perpetrator. The Met’s initial audit uncovered around 12,000 reports, while a more in-depth review highlighted more than 4,000 where the Crown Prosecution Service (CPS) or police had made a decision to take no further action. Susan Hall, the Conservative leader on the Greater London Authority (GLA), welcomed the fact that the grooming gangs problem in London was finally being noticedThose cases have now been passed to the NCA, which is expected to announce in the coming weeks how many must be reopened, according to the Telegraph.Ms Hall welcomed the fact that light was finally being shed on the problem in London. She told the paper that 'the mayor’s response was utterly disgraceful' and that it had been like getting 'blood out of a stone'.The Met commissioner Sir Mark Rowley has warned that he will need more resources and officers to deal with the caseload. But while many of the abusers identified in other parts of the country are predominantly Pakistani Muslim men, the issue in London is thought to be more complex. Not all the 4,000 cases identified by the Met fit the typical grooming gang model, with perpetrators and victims coming from a wide range of ethnic backgrounds.A source told the Telegraph the cases that had been reviewed were a mixture of intrafamilial, online and in-person abuse.But there is growing evidence that grooming gangs are still operating in the capital, with a BBC investigation in February finding that women and girls as young as 14 are being raped and forced into sex work.The broadcaster conducted interviews with five survivors of gang-based violence, showing that girls are being groomed into trading weapons, stealing phones and dealing drugs by groups of men.Some are being raped as 'payment' for unpaid drug debts accumulated by the gangs controlling them, while others are being groomed and forced into sex work by the organised crime groups.The gangs of men are from a range of different ethnicities, including white, and are exploiting women and young girls across England's capital city.A spokesman for Sir Sadiq in a statement rejected any suggestion that he had sought to cover up issues related to child sexual exploitation in London.He said the mayor 'welcomed' the reinvestigation of the cases, and had 'been clear we must leave no stone unturned'.The statement added that Sir Sadiq believes the groomed victims have not only suffered terrible abuse at the hands of the perpetrators but have been woefully let down by the authorities meant to protect them from harm.It explained that the mayor had strengthened the protection of children from exploitation by investing in specialist services, such as the £2.4million for specialist support for survivors of child sexual exploitation.The mayor also commissioned a 2023 inspection of the Met's child protection work by His Majesty's Inspectorate of Constabulary and Fire & Rescue Services, which found that it 'isn't doing enough' to protect children.The Met Dept Asst Commissioner Kevin Southworth said the force was fully committed to engaging with the National Inquiry and the Operation Beaconport review into past cases led by the NCA and the National Police Chiefs' Council (NPCC).He said it would work to deliver justice for the victim-survivors involved and urged anyone with any information to come forward.