CANADIAN police have arrested a computer expert alleged to be linked to a plot by al-Qaeda supporters to plant a lorry bomb in the heart of London.

Mohammad Momin Khawaja was held in Ottawa after a raid co-ordinated with Britain’s biggest counter- terrorist operation for decades.

Last night Mr Khawaja’s father, Mahboob, an outspoken critic of the United States, was reported to have vanished from his home in Saudi Arabia, where he is the administrator of a college.

His son was taken to court in shackles in Ottawa on Tuesday as 700 British police pounced on 24 homes and address across London and the Home Counties, arresting eight young Britons and seizing half a ton of ammonium nitrate.

The 29-year-old software designer, who was arrested at his office, works for the Canadian Department of Foreign Affairs and had visited London recently.

He is facing two charges of being involved in terrorist activity in Ottawa and London between November 10 and March 29. He appeared in court wearing a bulletproof vest.

At one stage agents hid in a van parked close to his family’s home in an Ottawa suburb and, after the arrest, they questioned other members of the family and searched for explosives or bomb-making equipment. The house where Mr Khawaja lives in Orleans, just outside Ottawa, was also raided after being placed under surveillance for a month.

Mr Khawaja, who worked on contract for the Canadian Government, is suspected of having travelled to Afghanistan and Pakistan as well as making trips to Britain, where he has family. He was shadowed by undercover agents while he was here.

One of his brothers, Qasim, said that he had come to Britain to find a wife and denied any links to terrorism. The family has a Pakistani background and Mr Khawaja, according to schoolfriends, became increasingly religious as he got older.

Scotland Yard and MI5 refused to comment about Mr Khawaja’s possible role in the alleged lorry bomb plot, but Canadian officers told how, at Britain’s request, they kept him under surveillance for more than a month.

The Globe and Mail newspaper in Canada reported that the dwelling was owned by his father, whose book Muslims and the West: Quest for Change and Resolution was published in 2000.

It examines Islamic fundamentalism, global conflicts and the Western world’s understanding of Islam. Dr Khawaja has also written several essays criticising United States foreign policy and the war on terrorism.

He is said to be a highly respected member of Ottawa’s 10,000-strong Pakistani community and is presently teaching at a university in Saudi Arabia.

Dr Khawaja told the Edmonton Journal that allegations against his son were false. “My children are not involved in this kind of thing. We are Canadian citizens and have lived there for a long, long, time. I don’t know what is the reasoning behind this whole adventure that they are undertaking with the context of international security. This whole thing sounds like a hoax and a very unusual adventure on the part of police.”

Originally from Pakistan’s Kashmir region, Dr Khawaja has lived in Ottawa for about 30 years but has worked extensively abroad, including in the United States and Saudi Arabia.

He received his masters of political science in 1981 and his doctorate in social science in 2001, both from Syracuse University in New York State.

During the 1970s he worked for the Canadian Government as a policy analyst for the Canada Post. Neighbours said Dr Khawaja had been away for about a moth but normally lived at the house with his wife Azra and four adult children.Yesterday his son Qasim said that he and his sister were separated and questioned for seven hours and police from the Mounties’ counter-terrorist unit took away computers and software. The Khawaja family moved to Canada in 1967 and all the children were born there.

In London, the eight suspects arrested in Operation Crevice faced a second day of questioning in the high- security wing of Paddington Green police station.

Two of the Britons had planned to leave the country next week.

Their families insisted that MI5 agents wanted to recruit Omar Khayam, 22, and his brother, Shujah, 17, as informants and had suggested that they go to Pakistan to infiltrate Islamic fundamentalist groups.

Ansar Khan, whose son, Ahmed, 18, is another of those being held, said: “They are teenagers. They can’t fix a tyre, they’re Manchester United fans and they’re nothing to do with terrorism.”

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