Ross Perot is addressing the Gulf War Syndrome inquiry in London

Mr Perot, and Congressman Bernie Sanders, are in a US delegation giving evidence at an inquiry in London into "Gulf war syndrome".

Support groups claim some 6,000 British veterans have suffered unexplained poor health since the 1991 war.

The MoD does not recognise the syndrome as a medical condition.

Speaking ahead of Monday's hearings, Congressman Sanders said he had spoken to "hundreds" of veterans from his own state of Vermont who were suffering "serious illnesses".

He compared the situation to Second World War veterans who were exposed to radiation and those hit by Agent Orange in Vietnam.

Estimate flawed

Giving evidence, Congressman Sanders said an American body, the General Accounting Office, had reported that techniques used by the British and American authorities to estimate levels of troop exposure to chemicals were flawed.

He said the Ministry of Defence had followed an American model to estimate that about 3,800 troops were "definitely" within the path of a plume or cloud filled with chemical agents which were released following the bombardment of Iraqi facilities in the first Gulf War.

But Congressman Sanders said the number of British soldiers who were potentially exposed to chemicals after the bombing of chemical facilities was "likely to be much higher than officially estimated".

Meanwhile Ross Perot, who was speaking ahead of his appearance on Tuesday, said troops close to Saddam Hussein's ammunition dumps when they were destroyed in the first Gulf conflict were more likely to fall ill.

"There is a fascinating correlation between proximity of the troops and the way the wind was blowing - there is a high incidence close to the bunkers," said Mr Perot.

Dr Keith Rhodes, one of the US experts who is also giving evidence, rejected suggestions that veterans were simply suffering from stress.

"Stress does not yield physiological changes in the brain," he said.

The inquiry is being funded by an anonymous donor and is being headed by a former judge, Lord Lloyd of Berwick.

It is being held in public and has already heard from veterans, medical and science experts, MPs and peers.

Military pensions

At the last hearing in July, Lord Craig of Radley, a former chief of defence staff, said the Ministry of Defence should compensate ill veterans of the first Gulf war.

Stress does not yield physiological changes in the brain Dr Keith Rhodes

Lord Craig told the inquiry the ministry should not move to require veterans to justify their illnesses.

Gulf war servicemen and women were inoculated against a variety of illnesses, including anthrax.

Some believe this left them suffering from complaints such as depression, memory loss, aching joints and tumours.

The MoD says there is no single cause of the illnesses suffered by veterans and that their symptoms are too varied to be considered part of a wider syndrome.

Some Gulf veterans have suffered from various complaints

Lord Bramall, chief of the defence staff from 1982 to 1985, told the inquiry the cocktail of vaccines given to Gulf war personnel may be partly to blame.