An ex-soldier has won a "landmark decision" to be awarded a disability pension for Gulf War Syndrome (GWS).
Many soldiers say they suffer from Gulf War Syndrome
The Pensions Appeal Tribunal (PAT) said GWS could be used as an "umbrella term" to cover the ailments suffered by Daniel Martin, 35.
The ex-guardsman, who suffers from memory problems, asthma and anxiety, said he felt "vindicated" by the ruling.
His case could potentially help hundreds of ex-servicemen.
Mr Martin, from Luton, Bedfordshire, welcomed the ruling, saying: "I am quite pleased, and I feel vindicated and very pleased for the good it might do to other servicemen.
"I don't know what to feel, really. It has been awful."
Mr Martin added: "I have had to see so many doctors and been knocked down so many times by the MoD and Veterans Agency, I feel pleased now that a court of law looked at all the evidence and came up with the conclusion I have known all along."
And Mark McGhee, of Linder Myers solicitors, who represented Mr Martin at the tribunal, said: "This is a landmark ruling.
"It is the definitive case on Gulf War Syndrome to date. Daniel stuck to his guns and has been vindicated, and this is going to have massive implications for hundreds of Gulf War veterans, who clearly suffer from Gulf War Syndrome."
The National Gulf Veterans and Families Association said that of the 7,500 veterans who have made a claim for a disablement pension, 1,500 have claimed GWS, and only two cases had been heard so far.
The tribunal, which hears appeals from ex-service staff who have had their claims for a war pension rejected by the secretary of state for defence, agreed with Lord Lloyd's previous inquiry in 2003.
That found that "veterans of the Gulf War later developed an excess of symptomatic ill-health over and above that to be expected in the normal course of events" and "there is a Gulf War health effect".
The judgment in Mr Martin's case differs from that in the case of a fellow Gulf War veteran, Shaun Rusling.
In Mr Rusling's case, decided in 2003, the onus was on the Ministry of Defence to prove that GWS did not exist.
In Mr Martin's case, the onus was on him to prove that he did have GWS.
His success has led Gulf War veterans to claim the Ministry of Defence "doesn't have a leg to stand on" in future cases.
The tribunal said: "The term Gulf War Syndrome is the appropriate medical label to be attached to this excess of symptoms and a useful umbrella for that label.
"It is highly regrettable that there was such a delay in the Ministry of Defence accepting this approach."
An independent inquiry last year said Gulf War Syndrome did exist and that soldiers who served in the Gulf were twice as likely to be sick than those who served elsewhere.
The inquiry report said illnesses suffered by veterans were likely to be due to a combination of causes.
These included multiple injections of vaccines, the use of organophosphate pesticides to spray tents, low level exposure to nerve gas, and the inhalation of depleted uranium dust.
However, the MoD dismissed the findings, maintaining that the illnesses suffered by veterans are so varied there can be no distinct syndrome or a specific cause.
The MoD said it was considering the tribunal's judgement, and would not comment on how the case could affect those of other ex-servicemen and women.
But a spokeswoman added: "We welcome the tribunal's decisions concerning the main issue which was placed before it.
"And that was that there is insufficient reliable evidence to indicate that GWS exists as a discreet pathological [disease causing] entity. It refers to a broad range of symptoms."
She added that Mr Martin had already been awarded a pension, on the grounds that he was suffering from psoriasis.
However, Mr Rusling, who is vice president of the National Gulf War Veterans and Families Association (NGVFA), said the judgement in Mr Martin's case was "very significant".
He said: "It means they haven't got a leg to stand on."
"Daniel Martin had to prove that he had GWS, and the Pensions Appeal Tribunal he has the condition."
He added: "We're now going to demand that the MoD deals with the other cases that are pending. There is no justification for not doing so."