The Metropolitan Police is facing a legal challenge over its use of facial recognition technology to spot potential suspects in crowds. Civil liberties group Big Brother Watch on Thursday launched what it described as a landmark legal challenge, with the backing of Baroness Jenny Jones.The facial recognition technology, which has been used for two years at Notting Hill Carnival, has wrongly identified people 98 percent of the time, leading to photos of over 100 people being stored on police databases without their knowledge, Big Brother Watch alleged.They described the Met's continued use of facial recognition software as “lawless growth of Orwellian surveillance.”Big Brother Watch said it has joined with Baroness Jenny Jones to demand an end to the police's use of real-time facial recognition cameras. Baroness Jones, a member of the House of Lords, fears that she could end up on a facial recognition watchlist when conducting her parliamentary and political duties. A photo of her was held on the Met's “domestic extremism” database and her political activities were monitored while she sat on an official committee scrutinising the Met and stood to be London's mayor.A legal letter sent to the Home Office, seen by Sky News, asked Home Secretary Sajid Javid to withdraw support for the technology or to demonstrate that facial recognition is being used proportionately and legitimately in reference to the European Convention of Human Rights.If this request is ignored, the group says it will take the case to court.A separate legal letter sent to Met Police Commissioner Cressida Dick, also seen by Sky News, sets out that the group and Baroness Jones see “the use of AFR (automated facial recognition) technology is unlawful”.