He said that Yusuf al-Qaradawi, a Qatar-based imam who is banned from America, was “an absolutely sane Islamist engaged with the world” who believed in democracy and an increasing role for women.
“Of all the Muslim leaders in the world today, Sheikh Qaradawi is the most powerfully progressive force for change and for engaging Islam with western values,” Mr Livingstone told the Commons home affairs select committee.
“I think his is very similar to the position of Pope John XXIII.”
The pontiff, who reigned from 1958 to 1963, was one of the great reforming popes and was credited with advancing co-operation with other religions. He met Protestant leaders, the head of the Greek Orthodox Church, the Archbishop of Canterbury, and a Shinto high priest.
Mr Livingstone said his view of al-Qaradawi was no different from an assessment offered by the Foreign Office when the Government was considering whether he should be prevented from attending a rally in Manchester held shortly after the July 7 bombs.
In the event, the imam did not travel to Britain, though his visit to London last year at Mr Livingstone’s invitation triggered protests from gay rights groups and Jewish leaders.
Mr Livingstone said that many of the comments attributed to the imam were “from translated sources hostile to him.” He was also not responsible for everything on the website that operates under his name.
The mayor conceded that he did not condemn “and may be prepared to endorse” suicide bombings in Israel because the Palestinians “only have their bodies” as weapons. His views were shared by a majority of Muslims, said Mr Livingstone.
He also said it was easy for those in the West to condemn all violence but “I don’t know what I would be doing if I was in Uzbekistan, dealing with that government.”
Asked about al-Qaradawi’s views on homosexuality – he is said to consider it an “abominable practice” and questioned whether gays should be put to death – Mr Livingstone said that much of his website was “a series of questions of a philosophical nature”.
He added: “We are clearly not going to see Dr Qaradawi on a gay rights march – but you wouldn’t see the Pope on a gay rights march and I would meet him.”
James Clappison, a Tory MP and a member of the committee, said that he found it hard to see any similarity between the imam and Pope John XXIII.
David Winnick, the Labour MP for Walsall, said if an extremist rabbi with objectionable views came to Britain, “would Mr Livingstone really welcome him and say all points of view must be heard.?”
Ann Widdecombe, the former Home Office minister who converted to Roman Catholicism after women were ordained priests in the Anglican church, said: “Ken Livingstone obviously has no idea either of the essentially holy nature of Pope John XXIII or the very dangerous nature of al-Qaradawi.”