TERRORISTS were planning to launch an unmanned plane from Suffolk to inflict an anthrax attack on the Houses of Parliament, it has been claimed.It has emerged a British terror suspect being held at a military jail in Guantanamo Bay, Cuba, allegedly confessed under duress to his part in the al Qaida plot.

TERRORISTS were planning to launch an unmanned plane from Suffolk to inflict an anthrax attack on the Houses of Parliament, it has been claimed.

It has emerged a British terror suspect being held at a military jail in Guantanamo Bay, Cuba, allegedly confessed under duress to his part in the al Qaida plot.

Moazzam Begg, 36, from Birmingham, is reported to have given the details last November.

It is claimed the father-of-three was going to fly an unmanned plane from Suffolk - the exact location in the county has not been specified - to London, dropping the bacteria over Westminster.

But his US-based lawyer, Clive Stafford Smith, said the statement was completely implausible and the alleged plot "laughable''.

The news emerged as human rights campaigners voiced concern over the treatment prisoners at Guantanamo Bay were receiving - claiming it was simply handing Islamic extremists an excuse to perpetuate attacks on America and her allies.

They also called for Prime Minister Tony Blair to make greater efforts on behalf of people detained in the "legal black hole" there.

Amnesty International delivered a letter to Downing Street yesterday ahead of the second anniversary of the prisoners arriving at the United States military jail in Cuba.

Moazzam Begg's father Azmat said yesterday: "We have had no letters from him since June last year.

"What they have done to him in that time we just don't know.''

Earlier, Mr Begg had interpreted references in a letter as an indication that Moazzam had been tortured.

The prisoner mentioned his fingernails were being treated and that he had been given ointment to apply to his body, said Mr Begg, 65, a retired bank manager.

"I'm terribly worried but at the same time I feel that his release is shortly coming,'' added Mr Begg.

"They can't keep him there for the rest of his life.''

News of the alleged terror attack being launched from a Suffolk airfield has prompted renewed warnings for people to stay on their guard.

Richard Spring, the Conservative West Suffolk MP, said: "These allegations just serve as a reminder that we have to stay on the ball with regards this kind of activity.

"However, I am confident that all of the airfields in Suffolk, of which there are a number within my constituency, have the correct procedures in place to prevent this type of thing from ever happening here."

Duncan Skeels, manager of Elmsett airfield, said: "Security around aircraft and airfields is of paramount importance.

"We have planning permission in place to build a new hangar later this year so as to fall in line with recent Home Office guidelines, issued in the wake of September 11.

"We have also received visits from Suffolk police's General Aviation Small Ports Unit and they have been very helpful in advising and consulting on measures to be taken.

"In short, I know that we have done, and continue to do, everything in our power to prevent any criminal activity coming out of Elmsett."

Mr Spring also spoke out on the release of the British detainees.

He said: "I believe that these men should be brought back to Britain to face trial and that each case should be dealt with individually from there.

"We have to consider each case on its merits. If there is evidence of acts of violence then a prosecution should follow, no doubt about that."