Police are investigating claims that up to five paedophile rings operated at the heart of Westminster with the involvement of highly influential" politicians. A Labour MP who has handed a dossier of evidence to Scotland Yard said he now believed the complexity of child abuse networks at the heart of government in the Seventies and Eighties had been seriously underestimated. John Mann, MP for Bassetlaw, said it was "inconceivable" that police would not now arrest and interview some of the politicians he has named in a list handed to detectives. Mr Mann, who has spent months sifting evidence from members of the public, met Scotland Yard and handed over evidence on 22 politicians, including three serving MPs and three members of the House of Lords. "There are at least five paedophile rings which involved MPs," he said. "Each of them involved at least one MP, some involved more, and these were groups of people who knew about the activities of one another. "In some cases I believe they committed abuse together." Thirteen former ministers were among the list. Mr Mann handed his dossier to detectives from Operation Trinity, the Metropolitan Police's investigation into alleged abuse in children's homes in Lambeth, south London. A range of other inquiries have also been launched including Operation Midland, looking at allegations of child sex abuse focusing on Westminster.