In 2010, George Henderson wrongly ticked a box saying he was unemployed while filling in the “tricky” application form for carer’s allowance. He had thought the Department for Work and Pensions was asking about his son John, who has learning difficulties and is addicted to heroin. Ticking that box has changed Henderson’s life. He said he was dragged through the courts, convicted of fraud and had to sell his home to pay back almost £20,000 in benefit overpayments after the DWP decided to prosecute him. The department recently acknowledged that Henderson had made an innocent mistake. Henderson is not alone. The Guardian society editor, Patrick Butler, tells Helen Pidd that he has been investigating why so many carers are being taken to court for benefit fraud. He explores what could be done to address a story that is drawing parallels with the Post Office Horizon IT scandal.