BBC Health Correspondent Fergus Walsh reports

It follows the chance discovery of proteins associated with the disease - the human form of Mad Cow Disease (BSE) - in the appendix of a patient who died last June.

Ethical rules for the tests are being prepared

The appendix was removed eight months before the patient displayed any symptoms of nvCJD, and nearly three years before he died.

There is currently no test for nvCJD in living people. Scientists who want to know if the UK is heading for an epidemic may now have a way of checking the wider population.

Listen to the reaction of scientists to the development

Hospital labs

Selected tests will be carried out on appendices and tonsils which are routinely kept in hospital laboratories after removal.

Sir Kenneth Calman: Tests will be anonymous at first

"This is a possible way of estimating the number of people who might be infected," said the Department of Health. "It's at an early stage. We haven't reached the point of any mass screening yet."

Researchers are preparing procedures and ethical rules for the initial studies which will receive funding through the Medical Research Council.

Sir Kenneth Calman: "A fortuitous discovery"

The Chief Medical Officer, Sir Kenneth Calman, said the tests would be done anonymously, but that could change if they revealed new cases of nvCJD.

"If there are, then I think we would move into a different mode with full involvement of individuals," he said.

Rogue protein

BBC Health Correspondent Fergus Walsh: "Potentially very significant development"

The case behind the latest development involved Tony Barrett, a coastguard from the South West.

His appendix was removed at Torbay hospital in Devon eight months before he displayed nvCJD symptoms.

When he died last year, neurologists went back to check the specimen and found evidence of the rogue protein associated with nv-CJD.

Currently, the only way of confirming a case of new-variant CJD is after a patient has died. This is done by examining brain tissue at post mortem - victims of CJD have fluid-filled cavities in their brains that give them a spongy appearance.

Infected beef

Tony Barrett's is one of 27 confirmed deaths from nvCDJ. The disease is a new form of a well established, although rare, illness that affects the central nervous system. It was linked to BSE-infected meat in 1996.

nvCJD was linked to BSE in 1996

Since then far-reaching measures have been taken to remove the possibility of infected beef getting into the human food chain.

Nevertheless, some scientists have estimated that, by the end of 1995, each member of the British public may still have eaten an average of 80 contaminated meals.

However, the scientists have no clear idea how many people will actually develop nvCJD. They hope Mr Barrett's case will provide some clues.

The local health authority has set up a helpline

Public reassurance

The surgical instruments used to remove Mr Barrett's appendix were also used in later operations. But Paul Courtney from the West Devon Health Authority stressed that all the equipment would have been thoroughly cleaned and sterilised.

Paul Courtney: The risks are minimal

"We want to reassure any other patients who may have had operations at that time that any risk of contamination by nvCDJ with the surgical instruments is absolutely minimal," he said.

A helpline has been opened for former patients who may be worried: 01803 861854.