An undercover police officer who infiltrated anarchist groups in the 1970s met a woman during his deployment and had a child with her, a public inquiry has heard. It appears to be the earliest known instance of a child being born from a relationship between a woman and an undercover officer who infiltrated political groups. The woman met the officer during his deployment when he was using the fake identity of Jim Pickford. The public inquiry heard that from the mid-1970s onwards, undercover officers who infiltrated political groups regularly formed sexual relationships with women. At least 20 police spies are known to have deceived women into sexual relationships until 2010, although the total number is currently unknown. At least two more women are known to have had children with undercover officers whom they met during the men’s deployments in the 1980s and 1990s. The inquiry, which is headed by a former judge, Sir John Mitting, is examining the conduct of about 139 undercover officers who spied on more than 1,000 political groups since 1968. The inquiry resumed on Wednesday and is due over the next three weeks to look at the activities of the undercover officers between 1973 and 1982. In a statement David Barr, the inquiry’s QC, said that during that period, there was evidence that at least five undercover officers “had sexual contact with as many as 12 different women”. He added the undercover officers working for the Special Demonstration Squad (SDS), a covert unit that monitored political groups, joked about the sexual relationships in the presence of their managers. The squad was all-male at that time. Barr said that Pickford, who has since died, infiltrated anarchist and community groups in south London between 1974 and 1976. He “met a woman in his undercover identity whom he went on to marry. [Pickford] and his third wife had a child together. The marriage did not last and ended in divorce”. Pickford told another undercover officer that he “wanted to tell her everything”. Barr did not give any further details. It is unclear if and when Pickford disclosed his real identity to her, when they got married or whether he was still in the police at the time of their wedding. Barr said: “It can safely be said that from the mid-1970s onwards, sexual contact between SDS officers in their undercover identities and members of the public was not uncommon.” The inquiry is due to question an undercover officer who adopted the fake name Vince Miller to infiltrate the Socialist Workers party between 1976 and 1979. He has said he had four “one night stands” while in his undercover identity. One of the women, known as Madeleine, disputes his claim and is also due to give evidence to the inquiry. “She states that there was a sexual relationship, initiated by Vince Miller, which lasted up to a couple of months and which occurred soon after the breakup of her marriage. It was not a casual thing for her and she was very upset when Vince Miller disappeared,” said Barr. Another spy, using the fake name Rick Gibson, infiltrated leftwing groups between 1974 and 1976. One witness has testified that Gibson “had sexual relations with at least four women in his undercover identity”, Barr said. One of these women, known as Mary, has told the inquiry: “Had I known he was a police officer there is absolutely no way I would have had any sexual contact with him at all.” She is due to testify that she believes that Gibson, who has since died, sought to “use sexual activity with her to bolster his cover”, Barr said. The inquiry continues.