A payroll review carried out by Northern Devon Healthcare Trust has revealed errors which led to 1,350 NHS workers receiving the wrong wages.The mistakes - which the trust said occurred when the service was provided by University Hospital Birmingham - mean staff now have to repay money which in some cases is understood to run into thousands of pounds.Of the 1,350 people, 406 were not paid enough and the trust said they would receive this in either the August or September pay runs. The trust decided to bring its payroll services back in house at the beginning of this year and to conduct a thorough review to unearth the mistakes it said had been made between December 2006 to December 2007 when the service was carried out elsewhere.Trust staff were told on Wednesday about the review's findings and the arrangements for handling both over and under payments.The figures appear to have emerged randomly, with several staff found to owe \u00A325 or less needing to do nothing as the money will be written off. But 577 owe more than that and will have to repay it. In a statement issued today (Friday, August 22) the trust said:"As a custodian of public funds, the trust is required to seek and recover all overpayment. "Explanatory letters were sent to the home addresses of the 577 staff owing more than \u00A325 on Wednesday, August 20. "Many staff, at all levels, had alerted the trust about overpayment when payroll was being handled by UHB. They were advised to keep this money separate pending the review, to make sure figures were accurate."Each member of staff has been offered the opportunity to discuss their individual circumstances and to agree a reasonable repayment schedule.The periods for repayment will be based on a sliding scale, varying from two months to 18 months, depending on the sums involved."It added that several people who no longer worked for the trust were also found to owe money and letters had also been sent to them, to begin the process of recovering it.Andy Robinson, Director of Finance and Performance, said they were "very sorry for any anxiety and hassle caused to staff during this review."He continued: "All the errors happened during the period of outsourcing to UHB, but the good news is that our payroll records are now finally accurate. This review brings the last 18 months of payroll errors to a close. "We're doing everything we can to pay people back quickly and are sympathetic to individual circumstances. It's perfectly understandable that staff with irregular shift patterns or overtime would not notice an overpayment. For those who do have to make repayments, we'll do our utmost to avoid financial hardship or anxiety.