A well-travelled British human rights activist and former Guantanamo Bay detainee said he was barred from boarding a direct flight from London to Toronto Friday because of concerns the aircraft could be diverted to the U.S.

Moazzam Begg was to speak at a Saturday conference on Islamophobia organized by the Canadian lawyer for Omar Khadr, 24, the Toronto-born Guantanamo prisoner convicted last fall of war crimes.

Begg said airline agents told him Canada’s High Commission in London informed them the issue was one of security. “They said to me the reason why they would not board me and take me to Canada is because, in the unlikely event they were rerouted to America, there could be a security concern,” Begg told the Star by telephone.

Air Canada, London’s High Commission and the Department of Foreign Affairs did not immediately have comment Friday.

Khadr’s lawyer, Dennis Edney, said a Canadian foreign affairs official informed him that Begg was denied entry due to a “U.S. policy.”

Esme Bailey, a spokesperson for Canada Border Service Agency said admissibility to Canada is “considered on a case-by-case basis and is based on information that is available to our border service officers at that time.”

Begg is the high-profile director of the London-based organization Cageprisoners, and has met with foreign ministers, deputy prime ministers and Britain’s Lord Chancellor through his advocacy work.

According to a diplomatic cable released through Wikileaks, the U.S. ambassador to Luxembourg had commended Begg as an ally in attempts to resettle Guantanamo detainees cleared for release.

Begg has never been charged in the U.S. or U.K. and, since his release from Guantanamo in January 2005 has traveled extensively through Europe, Asia and Africa.

“I’m being invited to a conference with lawyers, and it’s about community relations, so it would seem odd not to allow me in,” Begg said of Saturday’s conference in Richmond Hill. “But I guess it’s North America and North America is different from the rest of the world when it comes to these issues.”