Benefit sanctions are supposed to be part of a system helping people back to work. But critics say they penalise the vulnerable and are among the reasons for the growing use of food banks. So how fair is the Government's system of withholding state payments for those who don't comply with welfare rules? Allan Urry hears from whistleblowers who allege some JobCentrePlus staff are setting claimants up to fail in order to meet internal performance targets. Why did a recovering amputee lose his benefits because he didn't answer the phone?

Reporter: Allan Urry Producer: Nicola Dowling.