A social housing tenant is suing his landlord for £1m in damages, alleging that a housing officer illegally sublet his home when he was stranded abroad at the start of the Covid pandemic in 2020. Filippe Scalora’s case against Clarion will allege that when he returned to the flat he discovered a stranger had been sleeping in his bed and using his towels, cutlery, crockery and computer. The case over the one-bedroom property in Chelsea, south-west London, goes to trial at the high court in London on Thursday. Clarion is the UK’s largest housing association. “I walked into the flat and saw half of my stuff there and someone living in it,” the 43-year-old former regulatory compliance official told the Guardian. “My mail was open, really private stuff like bank accounts and NHS appointment forms. I was devastated.” Scalora was allocated the flat on Cale Street by the Royal Borough of Kensington and Chelsea (RBKC) with a lifetime tenancy because of a medical condition. The rent was about £600 a month but would cost roughly £2,000 a month on the open market, he said. He has been homeless since he returned to the UK, living in budget hotels and temporary accommodation. He said his home remained occupied by the person the housing officer moved in in 2020. Scalora was in Australia when the pandemic hit and claims he contacted his housing officer explaining he would not be able to get back to his home. He says the officer asked him to send his keys for a gas inspection and later told him RBKC wanted to allocate it to a temporary tenant. He said he was promised he would get his flat back, or another one, when he was able to return. His account is that when he realised he would be stranded abroad he asked a friend to remove his belongings to allow for the new occupant, but it would later transpire that not everything was removed. He discovered something was wrong in November 2021, when the housing officer stopped replying to his messages and the council told him it had no record of moving anyone else into the home. In April 2022 he returned to the UK and hired a locksmith to get him in, which was when he discovered another person had been living there. “It was very uncomfortable seeing someone had been sleeping in my bed, using my towels,” he said. “It was just theft.” Clarion declined to comment before the trial, where it will contest the case. It referred instead to a statement it made in October 2022 that a Clarion staff member, the unauthorised person residing in the home and Scalora were suspected of colluding to commit tenancy fraud and were under criminal investigation. That is something Scalora strongly denies. Scotland Yard said it had received a report that an “unknown person was believed to have been residing at the address while the occupier was abroad”, that the “tenancy issue was a matter for the relevant housing authority” and that no arrests had been made. It did not say Scalora was under investigation. RBKC said it had “established that any legal action had to be pursued by Clarion”. Scalora said he was interviewed under caution in late 2022 but the investigation did not proceed. Clarion said it had not been pursuing any legal action. About one in 20 social homes in London, and one in 30 elsewhere in England, are subject to some sort of tenancy fraud, according to a study by the Tenancy Fraud Forum and the Fraud Advisory Panel. It can include tenants subletting their properties on platforms such as Airbnb. RBKC has previously estimated that tenancy fraud costs the public purse an average of £42,000 a year for each home. With about 148,000 properties affected, the problem has been getting worse, with a shortage of affordable housing in the private sector, shrinking or stagnant incomes and pressure on budgets, staffing and skills among social housing providers considered the main drivers. Illegal subletting can net fraudsters thousands of pounds and is punishable by fines or up to two years in prison.