The children’s commissioner for England is due to visit Manston, the Home Office centre in Kent where small boat arrivals are processed, after concerns were raised about the treatment of children there, the Guardian has learned.It is not the first time the children’s commissioner, Dame Rachel de Souza, has intervened over the welfare of child asylum seekers. In a letter in January 2023 to the then home secretary, Suella Braverman, she raised concerns about reports that children had gone missing from Home Office accommodation.The Guardian understands that De Souza now has concerns about how children are processed at Manston – both those who are part of family units and those who are unaccompanied and are determined by Home Office officials to be adults despite insisting they are children.“The Home Office’s own guidelines on processing children at Manston are not being followed,” one source working at Manston told the Guardian. “There is a narrative that it is only young single men crossing the Channel in small boats but there are families, children who have been told by the Home Office that they’re adults, and pregnant women. It’s almost as if they’re pretending that there aren’t any children at Manston.“Just a few days ago I heard a child insisting to officials that he was 16 but he kept being told that was wrong and he was an adult. Children are not being properly age-assessed.”Other concerns include the way children are being processed alongside people that the source said may be traffickers. There has recently been an influx of young Vietnamese women arriving in small boats and some are believed to be accompanied by people who have brought them to the UK intending to exploit them here.“It’s a very hostile environment for children at Manston,” the source said. “The new arrivals often haven’t slept for days but small children here with parents are woken up in the night to do Home Office screening interviews and are sometimes forced to listen to harrowing accounts of rape and torture their parents give to officials when they are interviewed.”A second source at Manston said: “I have never before worked in an environment where the most vulnerable people are mixed with others who are potentially dangerous such as traffickers. I have written to managers about the toxic environment at Manston but nothing ever seems to get done.”A group of UN special rapporteurs recently raised concerns about rapid age assessment of newly arrived child asylum seekers leading to some children being treated as adults.Manston hit the headlines in the latter part of 2022 over a catalogue of problems including an outbreak of diphtheria – one man processed through Manston died after contracting it – severe overcrowding, unsanitary conditions, people being dumped on the streets of central London after being moved out of Manston, and claims of assaults by some of the guards.Although asylum seekers are only supposed to spend 24 hours at Manston, some spent more than a month there during that period. At least 96 asylum seekers who were at Manston at that time are bringing claims for false imprisonment, misfeasance in public office and human rights breaches.skip past newsletter promotionOur morning email breaks down the key stories of the day, telling you what’s happening and why it mattersPrivacy Notice: Newsletters may contain info about charities, online ads, and content funded by outside parties. For more information see our Privacy Policy. We use Google reCaptcha to protect our website and the Google Privacy Policy and Terms of Service apply.after newsletter promotionMaddie Harris, of Humans For Rights Network, which works with unaccompanied asylum-seeker children, said: “Since Manston opened, hundreds of children wrongly treated as adults have spent days and previously sometimes weeks held there. Children have told us that despite repeatedly telling staff there they are children they are ignored, placed in tents and exposed to significant harm and trauma.“These children, whilst having their screening interviews at Manston, are again telling immigration officers that they are children. However, no steps are taken to safeguard or protect them.”The office of the children’s commissioner for England confirmed that they were due to visit Manston imminently after a series of concerns were raised with them about the welfare of children.The Home Office has been approached for comment.