A former undercover police officer has told a public inquiry that his colleagues made “gross and offensive” jokes about the women they were deceiving into having sexual relationships. The officer, Graham Coates, said the jokes and banter were said in the presence of managers who knew about the relationships but deliberately turned a blind eye. He said the attitude among the officers to the relationships “could best be summed up as “good on you”, “well done”, “go for it”.” Coates is the first undercover officer who has testified to the inquiry that the managers of the police spies knew they were forming relationships with women during their deployments. He added that managers “across the board” were “not troubled” by the sexual relationships and did not express any “outright criticism or disapproval” of the undercover officers. “It was made quite plain with jokes and banter that they knew, we knew and management knew what was going on,” he said. On Friday, Coates gave evidence to the judge-led public inquiry that is scrutinising the activities of about 139 undercover officers who spied on more than 1,000 political groups since 1968. In hearings that started last year, a succession of undercover officers, who were seen as professional intelligence-gatherers in an elite unit, have testified that they knew nothing about the sexual relationships. David Barr, the inquiry’s QC, has said that from the mid-1970s, these relationships were common. At least 20 undercover officers deceived women into intimate relationships while they infiltrated political groups in the decades up to 2010. At least three of them fathered children with women they met while undercover. Coates said there was no appreciation among the undercover officers of how the women would have felt if they had heard the comments. He said there was a “tacit acceptance” among managers that undercover officers who had sexual relationships gathered better information about the political groups they were infiltrating. Coates said: “I don’t think managers were weak but it seemed as though they were deliberately blind in some areas such as sexual activity by undercover officers while undercover.” He spied on anarchist and leftwing groups between 1976 and 1979 while a member of Scotland Yard’s Special Demonstration Squad (SDS), which infiltrated political groups for four decades. Referring to what he called “communal humour”, he said the “jokey remarks” about sexual relationships were made at SDS meetings attended by the managers. “I do not recall anyone challenging the behaviour of the undercover officers when jokes were made about sexual activity or relationships in SDS meetings. “As far as I am aware, these jokes never prompted a question about where to draw the line or resulted in disciplinary action. “No one encouraged undercover officers to engage in sexual activity while undercover but the managers appeared to turn a blind eye to the bits of banter and innuendo I heard.” Coates suggested the jokes related to women who had relationships with three undercover officers in the SDS at that time. He identified Jim Pickford, who infiltrated anarchist and community groups between 1974 and 1976. Pickford met a woman while undercover and later had a child with her. Coates also said another spy, Rick Gibson, “had his leg pulled during a group discussion … about a sexual encounter”. The inquiry has been told that Gibson, who also infiltrated leftwing groups between 1974 and 1976, deceived four women into intimate relationships during his deployment. Coates recalled a comment from an SDS officer along the lines of “he’ll have made her bite the blankets again last night”. He said: “In hindsight, I think there should have been much stricter guidance in terms of the potential damage of such relationships to individuals and families and that intimate relationships by undercover officers should have been discouraged.” In recent years, the Met has admitted the undercover officers formed “abusive and deceitful” relationships with at least 12 women and paid them compensation, after they took legal action. Last month, Phillippa Kaufmann, a QC representing 21 women, told the inquiry that the “endemic” practice of undercover officers deceiving women into relationships resulted from “systemic and long-running sexism … which allowed officers and their superiors to think it was acceptable to engage in such abusive practices.”