The veterans, campaigning over Gulf War syndrome, believe they are being harassed as "subversives" by officials because of their attempts to find out what happened to them in the war.
One of those who has been targeted is Angus Parker, who served as a technician for a secret Gulf unit working for scientists from Porton Down, the chemical defence establishment in Wiltshire.
Mr Parker, who is now showing the symptoms of Gulf War syndrome, tipped off the Commons Defence Select Committee about the work of his unit.
Soon afterwards, he visited London to be assessed by Army doctors. As he left the Henry VIII hotel, Bayswater, on the morning of 5 February, he was followed into a nearby cafe by a man in a suit.
The man, who knew Mr Parker was going for a medical, asked the veteran whether he intended to make any more information public, and refused to identify himself.
An argument ensued and the interrogator left. Then 10 days later, he reappeared, following Mr Parker outside his home in Newcastle-upon-Tyne.
Mr Parker, who suffers from respiratory problems, unsuccessfully tried to chase the man, who had a military-style haircut and a southern accent.
Earl Howe has agreed to meet Mr Parker at Westminster today, when the matter will be discussed along with other grievances regarding Gulf War syndrome. "We are seeking medical recognition of our condition and we are being tarred with the same brush as subversives," said Mr Parker. "We are fine upstanding members of society, willing to fight and die for our country, and look what is happening to us."
Dr David Clark, Labour's defence spokesman, said: "I am alarmed that the Gulf vets are being harassed in such a frightening manner. It appears that the Government are trying to hide something even now. Instead of harassing these people, the Government ought to help them find out what's wrong with them."
Dr Clark has also been given details of the alleged harassment of a former Army private from North Wales. The man claims that he was threatened by a group of men who would not identify themselves but knew of his campaign for compensation for sick Gulf troops.Reuse content