Sheikh Yusuf al-Qaradawi, as respectful supporters address him, is a complex, international figure, whose religious pronouncements address the dilemmas confronting Muslims in the modern world.
To many in the Middle East, the 77-year-old scholar is recognised more for having spoken out in condemnation of al-Qaida's indiscriminate massacres than for supporting suicide bombers in Israel. He does not fit into the common stereotype of fundamentalist, militant preacher.
Mr Qaradawi, who has been based in the Gulf state of Qatar since 1961, has repeatedly endorsed the cause of women's political rights in the Islamic world but has also declared that Islam allows men to smack their wives where it is "necessary".
His faith and political roots lie in Egypt's Muslim Brotherhood, which was founded in 1928 to combat the secular influences of western civilisation and replace them with lslamic laws and values. It is banned in Egypt, where its members were implicated in the 1981 assassination of President Anwar Sadat.
He had reputedly memorised the whole of the Koran by the age of 10. He rejected his parents' suggestion that he become a carpenter and instead studied at Al-Azhar, the Cairo university recognised as the principal doctrinal training college in the Sunni branch of Islam.
He was imprisoned at least three times in his youth. One of his contemporaries was Sayyid Qutb, the man who provided the ideological basis for al-Qaida.
But Mr Qaradawi, who was reportedly tortured during his time in jail, left Egypt in 1961. He has been described as the spiritual leader of the Muslim Brotherhood but has twice rejected a formal offer to become the group's leader.
There have been suggestions that he has distanced himself from the organisation, which has tried to move into constitutional politics. The Brotherhood's place as the radical edge of Islamist insurrection has long been usurped by al-Qaida and other militant factions.
Although well known as a scholar, Mr Qaradawi rose to international prominence in the late 90s with the rise of pan-Arab television stations. On his weekly TV show on al-Jazeera, called Islamic Law and Life, he gives his interpretation of Islam on a wide range of subjects.
Although such religious rulings are usually local affairs, his show has made him a household name.
Depending on whose opinion you take, he is either a nuanced scholar or a flip-flopping populist, a liberal or a radical, a fundamentalist or a heretic.
His stance over the Israeli-Palestinian conflict is one example. Mr Qaradawi has insisted the conflict is about land only and has distinguished between Israelis and the Jewish community. That might make him a moderate to some in the west.
But he has also argued that suicide bombers are a legitimate method of attack for Palestinians. Such criticisms led to a ban on entering the US, which has been in force since 1999.
Followers of the strict Wahhabi tradition of Islam dismiss him as a heretic because of his engagement with the modern world and because they believe there is a fundamental religious conflict between Jews and Muslims.
Mr Qaradawi flew into London this week to chair the annual meeting of the Dublin- based European Council for Fatwa and Research, of which he is president.
On this visit he has attended a meeting of the Oxford Centre for Islamic Studies, of which he is a trustee. He had planned to speak at a Muslim youth conference this weekend but pulled out yesterday.
He had been expected to tell them that they have two responsibilities: to preserve their Muslim identity, and to be model citizens of the country.
Mr Qaradawi has been wary about giving lengthy interviews to the UK media. He is known to feel that the coverage has been "vicious" and unbalanced.
According to Azzam Tamimi, a member of the Muslim Association of Britain, who is translating for the Arabic-speaking Mr Qaradawi, the cleric did not want to be "drawn into the gutter" by answering questions on his views on homosexuality or wife-beating taken from websites.
Dr Tamimi said the media had narrowed the focus of discussion to suicide bombing, pointing out that Mr Qaradawi has written about a wide range of topics: "He is a jurist. If you ask him about these issues he will tell you the Islamic position of the Koran. These aren't his views. He is not a politician."
As he was ushered into the crowded chamber at the Greater London assembly on Wednesday afternoon, he appeared genuinely puzzled by the furore.
Wearing a white and burgundy Egyptian-style headdress and a long brown robe, Mr Qaradawi delivered his opinions in a powerful, resonant voice.
"London," he said, "is a city of cultural plurality. [We urge] Muslims to integrate into the societies within which they live without conceding their faith."