Stephen Hawking’s decision to join the academic boycott of Israel has prompted anger from the organisers of a conference he was due to address.

The acclaimed physicist and author of A Brief History of Time was due to be the keynote speaker at the fifth President’s Conference hosted by Israeli President Shimon Peres next month. But he has told Mr Peres that he will not be attending “based on his knowledge of Palestine”.

Conference chairman Israel Maimon said: “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 Law Centre, a civil liberties group, told Wired magazine that in order to be consistent, Prof Hawking should now pull the Israeli-designed Intel chip out of the computer that enables him to talk.

A spokesman for anti-boycott group Fair Play commented: “Professor Hawking’s misguided withdrawal from the President’s Conference is both bizarre and unfortunate. President Shimon Peres is one of Israel’s strongest and most consistent advocates for peace.”

There was confusion when a Cambridge University spokesman initially rejected the claim that Prof Hawking was boycotting Israel, saying the scientist had withdrawn on “health grounds, having been advised by doctors not to fly.” Hours later, however, it was confirmed that it was a boycott.

This year’s conference will celebrate Mr Peres’s 90th birthday with guests including former US President Bill Clinton, former President of the USSR Mikhail Gorbachev, former British Prime Minister Tony Blair and Barbra Streisand.