An undercover police officer “bragged” that he had fathered a child with an activist from whom he had concealed his real identity, a public inquiry has heard. The officer, Bob Lambert, had the child with the woman, known only as Jacqui, while he was infiltrating animal rights and anarchist groups. One of his colleagues alleged that this was “common knowledge” within the secret Scotland Yard unit they worked for. The inquiry heard on Monday that Lambert told two of the unit’s managers that he believed he was the father of the child, and both decided to do nothing. Lambert abandoned Jacqui and his son when he was two years old, leaving her to bring him up on her own in difficult circumstances. She only found out – by chance – more than two decades later that he had been an undercover officer sent to spy on activists, and not the committed campaigner he portrayed himself to be. The discovery has left her devastated and contemplating suicide. The inquiry heard evidence for the first time that Lambert’s managers had been told at the time that he had fathered a child while he was infiltrating political campaigners. Lambert was later awarded a commendation for gathering information about activists during a successful operation. Sir John Mitting, the retired judge heading the inquiry, is examining the conduct of about 139 undercover officers who spied on more than 1,000 mainly leftwing groups between 1968 and at least 2010. One of the main issues is how officers frequently formed intimate relationships with women without disclosing that they were undercover spies. The current phase of the inquiry is concentrating on the deployments of undercover officers during the 1980s and 1990s. During his four years undercover, Lambert deceived at least four women into sexual relationships. Jacqui has described how she quickly became smitten by the “very charming and charismatic” Lambert in 1984. Their son was born the following year. On the weekend she went into labour, she was unaware that he had been with his wife and two children. Jacqui has said he had made no effort to persuade her to have an abortion. Initially he was a devoted, hands-on father, but disappeared around 1988, claiming that he had to go on the run abroad to escape from the police who wanted to arrest him over his animal rights campaigning. Jacqui only found out Lambert’s true identity in 2012 when she stumbled across an article about his undercover work in a newspaper. He had not made any attempt to trace her or their son. On Monday, the inquiry heard that Mike Chitty, another undercover officer in the unit, alleged that “Lambert bragged about fathering a child through a relationship while deployed and that it was common knowledge in the office at the time that Lambert had fathered a child”. Chitty made this claim to two previous internal police investigations. The current inquiry has been unable to obtain evidence from Chitty, who lives abroad. The inquiry heard that Chitty had a “strong dislike” of Lambert, who denies the claim. David Barr, the inquiry’s KC, said Lambert had admitted that he had “informally” told one of his managers, Michael Barber, that Jacqui was pregnant “and that he believed that he was the father”. “According to Lambert, the conversation took place in a pub and concluded with DI Barber deciding that he did not need to report the matter and leaving Lambert to deal with the situation.” Barber has since died. Peter Skelton, the Metropolitan police’s KC, said Tony Wait, the then head of the covert unit, had accepted that Lambert had told him “that a woman with whom he had been having an association was pregnant”. Lambert later said he was not necessarily the father. Wait discussed this with another manager “and decided not to take any action or make any further inquiry”, added Skelton. This was “wholly wrong”, said Skelton. The Met has paid £425,000 to Jacqui in compensation and an undisclosed sum to her son. He has suffered psychiatric damage after discovering the truth about his father at the age of 26. Four undercover officers are known or alleged to have fathered children with women they met during their covert operations.