Millions of pounds are being wasted on paying suspended NHS staff to do nothing, Whitehall's spending watchdog has warned.

The National Audit Office raised concerns on Thursday about the length of time spent by clinical staff suspended or sent on gardening leave.

It found that by July last year 1,000 clinical staff were excluded on full pay from the NHS at a cost of around £40 million.

The report also questioned the fairness, openness and transparency of the disciplinary process.

The public spending watchdog called on the Department of Health, strategic health authorities and NHS trusts to take immediate action.

In one case, a NHS worker had been suspended for four years.

Just cutting the procedure to six months would save £14 million, the NAO calculated.

The watchdog highlighted the fact that 40 per cent of the doctors returned to work when their complaint had been resolved.

Being subjected to a drawn-out process left many with reduced self-esteem and depression. A number never work again, even if exonerated.

NHS trusts were slammed for rushing to exclude staff without considering alternatives such as restricting activities.

"There is evidence of many cases of exclusion being allowed to drift on without resolution or proper management," said NAO chief Sir John Bourn.

"This represents a serious waste of resources for the NHS and can harm the career and even personal well-being of the accused clinicians themselves."