Tariq Ramadan is the grandson of the founder of the Muslim Brotherhood

Professor Tariq Ramadan, who lives in Geneva, was named as one of the 21st Century's great innovators by Time Magazine last year for his work.

But he was unable to take up a position teaching at Notre Dame University in the US when the Dept of Homelands Security revoked his visa in July 2004.

St Antony's College says he is due to begin a Visiting Fellowship in October.

Professor Ramadan, 38, is the grandson of Hassan al-Banna, who founded the prominent Islamic movement the Muslim Brotherhood in 1928.

He has been accused of supporting attacks in Israel and Iraq. He publicly condemned the 11 September and London attacks and says he is against the taking of innocent life.

St Antony's college is a forum for free academic exchange on the issues of our times College spokesperson Prof Tariq Ramadan

Shortly after the London bombings The Sun newspaper ran a front page story criticising a decision to invite him for a conference - entitled Meet Islamic Militant Professor Tariq Ramadan.

Professor Ramadan called on Muslims to condemn the attacks on London "with the strongest energy".

He said: "Criminals, no doubt, will continue to kill, but we shall be able to respond to them by demonstrating that our experience of human brotherhood and mutual respect is stronger than their message of hate."

A college spokesperson said: "Professor Ramadan is an internationally-recognised scholar.

"Professor Ramadan is a regular visitor to Britain and the other states of the EU, without exception.

"St Antony's college is a forum for free academic exchange on the issues of our times, and opposes all manifestations of hate speech and intimidation designed to curb academic freedoms."