A migrant processing centre in Kent is “catastrophically overcrowded”, with people waiting for their asylum applications to be processed kept in inhumane conditions and guards not being trained properly, a union leader says. Criticism of the government’s handling of the facility is mounting, with the chair of a parliamentary select committee saying a “crisis” was brewing given the backlog in the UK of more than 100,000 cases. Nadhim Zahawi, the Conservative party chair, said it was a “tough problem” trying to stop migrants being smuggled across the Channel in small boats. He said ministers were doing “everything to unblock the blockages” in the asylum processing system, while working “upstream” with the government of Albania, from where he claimed 80% of arrivals were now coming. The spotlight on the Manston processing site intensified earlier this week when the independent chief inspector of borders and immigration said he was left speechless by its “wretched conditions” and had discovered some of the guards on site had no qualifications to do their job. Migrants are meant to be held at the facility, which opened in January, for 24 hours while they undergo checks before being moved into immigration detention centres or asylum accommodation, currently hotels. Officials have confirmed about 3,000 people are being held there on a site designed for 1,000 with a maximum of 1,600. Those being held were not being kept in “humane conditions”, said Lucy Moreton, a spokesperson for the ISU union that represents border, immigration and customs officials. Speaking on BBC Radio 4’s Today programme, she said: “The individuals there, both the contractor and the immigration staff, have no training as prison officers or in public order situations and yet are being called upon on a daily basis to intervene. “The migrants aren’t being kept in humane conditions – they don’t have any enrichment, they don’t have anything to do, they’re bored, they’re frustrated and understandably they scrap among themselves and with us. “It’s not their fault they’re in that situation. In fairness, it’s not Border Force or immigration enforcement’s fault. There’s no housing upstream so we can’t move them on.” Diana Johnson, a Labour MP who chairs the home affairs select committee, said the asylum and immigration systems were in crisis. More than 100,000 asylum claims were waiting to be decided, she said, making the processing centre “gummed up” for “weeks on end” as migrants could not move through the system, while those waiting for their claims to be processed stayed in hotels, costing the government what she said was about £7m a day. Recent costs have been estimated at £4.7m a day. Johnson said government support to work more quickly through the backlog would “free up resources and would make the system much swifter”. She also called on ministers to “establish some safe and legal routes so people can make asylum claims”. Zahawi defended the government’s record, despite it failing on its longstanding promise to reduce the number of migrants arriving on small boats across the Channel. He said the home secretary, Suella Braverman, under fire for her reappointment a week after being forced to quit for breaching the ministerial code, was working to get the Rwanda removal scheme up and running. “There’s some obviously legal challenge to that at the moment,” he said. “When we get the outcome of those we’ll be able to move forward.” A Home Office spokesperson said: “The continued rise in dangerous small boat crossings is causing an unprecedented strain on our asylum system. “Manston is resourced and equipped to process migrants securely and we will provide alternative accommodation as soon as possible. “We urge anyone who is thinking about leaving a safe country and risking their lives at the hands of people smugglers to reconsider. Despite what they have been told, they will not be allowed to start a new life here.”