At least 25 undercover police officers tricked activists into having sex with them , new figures reveal. The spy cops were members of a shadowy police unit whose members are known to have slept with at least 50 women over four decades. Two of the 25 officers were women and the relationships began in the 1970s and ended in 2010. Four women are alleged to have had children with police officers who were posing as campaigners while using fake identities. It comes as the story of a secret unit paid