Steven Hawking, the leading physicist, has become embroiled in a dispute over what he sees as the occupation of Palestinian territory after he boycotted a major Israeli conference.
At first Hawking's home base, UK's prestigious Cambridge University, claimed that Hawking would not be attending the high profile Israeli Presidential Conference, which is personally sponsored by Israeli president Shimon Peres, for health reasons.
But last night it emerged Professor Hawking had written to the organizers, stating his intention to boycott the event because of Israel's presence in what he sees as Palestinian territory.
His letter stated: "I accepted the invitation to the Presidential Conference with the intention that this would not only allow me to express my opinion on the prospects for a peace settlement but also because it would allow me to lecture on the West Bank.
"However, I have received a number of emails from Palestinian academics. They are unanimous that I should respect the boycott. In view of this, I must withdraw from the conference. Had I attended, I would have stated my opinion that the policy of the present Israeli government is likely to lead to disaster."
His withdrawal, dated May 3, drew s stern rebuke from Israel Maimon, director of the conference: "The academic boycott against Israel is in our view outrageous and improper, certainly for someone for whom the spirit of liberty lies at the basis of his human and academic mission.
"Israel is a democracy in which all individuals are free to express their opinions, whatever they may be. The imposition of a boycott is incompatible with open, democratic dialogue."
The Wolf Foundation, which awarded Hawking the Wolf prize in physics in 1988, said it was "sad to learn that someone of Professor Hawking's standing chose to capitulate to irrelevant pressures and will refrain from visiting Israel".
But the Boycott, Divestment and Sanctions movement, which aims to apply pressure to Israel, said Palestinians 'deeply appreciated' ' Professor Hawking's decision.
Professor Hawking has had Motor Neurone Disease for 50 years and has used a wheelchair for most of his life. He also requires mechanical help to speak.