Ministers say the cash is being creamed off from hospitals, GP practices, dental surgeries and other NHS facilities through dozens of scams.

That £80m stolen each year is enough to pay for an extra 4,275 nurses, or 684 consultants, say ministers. Spent on medical procedures, it would fund an extra 11,400 hip operations or more than half a million MRI scans.

But the claims have caused widespread anger among medical staff, who have accused the Government of risking a morale crisis by casting suspicion over the entire health service.

The SNP Government says fraud committed by staff and patients totals as much as £100m annually. But a senior official, who asked not to be identified, told Scotland on Sunday that staff were responsible for the vast majority of the losses, as much as £80m a year.

The Government's hard- hitting assessment of NHS scams reveals:

• GPs claiming for treatment which was never given, home visits never made or non-existent "ghost" patients.

• Hospital doctors claiming payments for private work undertaken during NHS time or on NHS premises, and misuse of NHS fuel and credit cards.

• Nurses making fraudulent travel and overnight claims, and moonlighting on lucrative shifts for nursing agencies while claiming to be off sick.

• Pharmacists making claims on the NHS for expensive brand-name drugs when they actually dispensed cheaper generic alternatives.

• Dentists claiming money for precious metals in fillings when they had actually used cheaper materials, and claiming cash for opening surgeries for after-hours emergencies when the premises were already open.

• Opticians claiming for two pairs of glasses when only one pair was supplied.

Other scams include staff printing off prescriptions for drugs under patients' names, deleting the transaction from the computer, then pocketing the drugs for their own use.

The crackdown will be officially launched tomorrow by Scottish Health Secretary Nicola Sturgeon, who said: "Let me make it clear that fraud in the NHS will not be tolerated. While only a tiny minority of people defraud the NHS, their actions cost the service dear. NHS fraud takes money away from where it is needed most. We are therefore determined to ensure that the problem of fraud is tackled effectively."

Each health board will have an "anti-fraud champion" and health service managers will be given training in how to spot fraud and what to do about it.

An anti-fraud source in the NHS said: "What we're wanting to do is deter people from getting involved in fraud in the first place because at the end of the day that is much more cost-effective than investigating each incident. But we want

people to know that we are watching and we have powers to refer cases to the procurator fiscal."

Dr Kevin Cormack, Scottish spokesman for junior doctors' lobby group Remedy UK, said: "If anyone is letting the people down when it comes to public services, it's politicians rather than health workers. All the NHS staff I have ever encountered are honest and altruistic."

Bridget Hunter, of health union Unison in Scotland, said: "We don't condone fraud, but we are very concerned at the emphasis in all of this. It's like they're telling staff: 'We don't trust you.' The Government risks giving a very wrong impression of NHS staff who all work to the highest professional standards under very challenging conditions."

A spokeswoman for the doctors' union BMA Scotland said: "You can't just single out individual groups such as GPs and staff and suggest that they bear the brunt of this."

But Margaret Watt, of the Scottish Patients' Association, said: "This does need to be taken very seriously, whether frauds are carried out by patients or staff. Every fraud is stealing from the sick, the vulnerable and the dying."

Last year a Fife nurse was sentenced to 135 hours' community service for claiming £3,000 sick pay while working shifts for an agency.