A blunder by health bosses resulted in staff who had left their NHS jobs still being paid their wages.

At least one care assistant was paid an extra £20,000 over 20 months after she moved to a neighbouring NHS trust.

It has emerged that three similar Sussex cases have been investigated by the NHS counter-fraud team.

NHS paymasters along with administrators at South Downs NHS Trust failed to spot the mistake after the Trust's payroll system changed in 2007.

Executives have admitted the blunder and apologised, saying steps have been taken to ensure it does not happen again.

The mistake did not come to light until two years after care assistant Karen Tovey quit her job with the Trust at Brighton General Hospital in 2007.

She moved to St Leonards where she got a similar job working for neighbouring East Sussex Hospitals NHS Trust at the Conquest Hospital.

At the same time the payroll system at South Downs was changed and wages from Tovey's old job continued to be paid into her bank account.

Tovey, 27, realised what was happening but did not inform her old bosses and the fact that she was being paid twice was not spotted by the NHS.

Her dishonesty emerged when South Downs brought in another payroll system last year.

By that time she had been paid £19,552 she was not entitled to, Hove Crown Court was told yesterday.

Tovey, of Longacre Close, St Leonards, was given a nine month prison sentence suspended for two years after she admitted obtaining wrongful credit from her employees.

The maximum sentence is ten years in prison.

She must also do 100 hours of unpaid community work within 12 months.

Tovey had not told her new bosses at East Sussex Trust that she was being prosecuted and is still working there.

NHS fraud investigators confirmed that at least two other workers at South Downs have been prosecuted and a third is under investigation, all for much smaller amounts.

Chris Lovegrove, of the NHS counter fraud team said: “The trust has acknowledged there was an error on its part and supported our investigation.

“There was a time when, because of the changes at the Trust, there was an issue with forms not being completed or systems updated.

“There were a number of people there who continued to be paid salaries after they left.

“However, it was still down to the individual to accept that they had been paid incorrectly and declare it to the Trust rather than spend the money.”

He added that Tovey should have told her new NHS bosses that she was facing prosecution.

He said as a result of her conviction her future employment at East Sussex NHS Trust will now be considered.

Ed Fish, defending, said Tovey had not deliberately set out to deceive the Trust.

He said she was persuaded to keep the money because her husband is a gambler and they had debts, including owing £2,000 in council tax.

A spokesman for South Downs NHS Trust said: “The Trust has learned from its mistakes. The new system is rigorous and demands a high level of management awareness and accountability.

“The Trust recognises its responsibility when dealing with public money and that it is responsible for ensuring that every penny is spent appropriately and to maximum effect.”