Rather than impose any visa restrictions, the British government has told Washington it would prefer if the Americans simply deported Britons who failed screening once they arrived at an airport in the United States, British officials said. The British also screen at their end, and share intelligence with the Americans.  But Washington feels strongly, Mr. Chertoff has said, that it has the right to build controls against terrorists from Britain who do not have a prior criminal record — precisely the kind of man Mr. Khyam was until he was arrested in early 2004 and put on trial for plotting to blow up targets like a major London nightclub and a popular suburban shopping mall.  For its part, the British government looks with dismay at the frequency with which Britons travel to their ancestral land of Pakistan — an estimated 400,000 trips a year — where a small minority, like Mr. Khyam, link up with extremist groups and acquire training in weapons and explosives.  Foreign office officials have said they have discussed measures with the Pakistani Embassy in London, which grants Pakistani passports to Britons of Pakistani descent, to consider tightening the rules for Pakistani travel documents.  In Washington, an expert on terrorism and Pakistan, Bruce Riedel, who served on the National Security Council under President Clinton and in the early Bush administration, and who recently retired after 30 years in the Central Intelligence Agency, said that Mr. Khyam was perfect material for Al Qaeda.  “He is the classic U.K.-Pakistani connection that Al Qaeda has focused on since 9/11,” said Mr. Riedel, who is now a senior fellow at the Brookings Institution in Washington. “His U.K. passport gives him international mobility. His training at a camp run for Kashmiris by Pakistan’s Inter-Services Intelligence agency gives him expertise. Al Qaeda gives him direction.”  The trial that ended Monday with the conviction of Mr. Khyam and four other Muslim men on conspiracy charges did not establish whether Mr. Khyam or his colleagues belonged to a Qaeda cell.  But the head of counterterrorism at Scotland Yard, Peter Clarke, said after the verdict the investigations into the bomb plot had given “a new understanding of the Al Qaeda threat to Britain.”  At his sentencing, the judge, Sir Michael Astill, described Mr. Khyam as “the energy behind the conspiracy,” the man who attracted other young Muslims to the plan, and inspired them, and who knew how to shuttle from Britain to Pakistan for terrorism training.  From Mr. Khyam’s own testimony, as well as a cascade of official intelligence surveillance presented during the yearlong trial, a portrait of determination and ruthlessness emerged.  As a teenager, Omar became entranced by jihadist ideology. He moved on to the cause of Kashmir, and was then piqued by 9/11 and the Iraq war, things that inspired and angered other Britons with Pakistani roots. But he in the end turned to attacking Britain, where he was born and raised.  Asked on the witness stand his reaction to 9/11, Mr. Khyam did not disguise his delight.  “I was happy,” he recalled in his south England accent. “America was, and still is, the greatest enemy of Islam. I was happy that America had been hit because of what it represented against the Muslims, but obviously 3,000 people died, so there were mixed feelings.”  Mr. Khyam testified that his parents migrated to Britain from Pakistan in the 1970s, before his birth. He came from a family, he said, with a proud heritage of service, first in the British Army in Pakistan, then in the army of the newly independent Pakistan, and also in the intelligence services.  His parents were not particularly religious, he said, a pattern typical among Pakistani immigrants to Britain where the new generation, often turned off by what they see as the loose morals of binge drinking and broken marriages, has proven to be more devout than their elders.  At the age of 10, his father, a successful businessman with a textile factory in Karachi, left his mother and moved to Belgium, leaving behind Omar, the eldest, and two small children.  His mother’s English was poor. Quickly, Omar became the man of the household, organizing the finances, and bossing his siblings. Instead of enrolling in the local school where most of the students were South Asian, he attended a mostly white, government-run school, and led a middle-class British life.  He did relatively well in his final school exams and enrolled in college but, distracted by his larger cause, never followed through on his studies or sought steady employment.  By 1998, he had taken his first steps into the realm of radical Islam, when he was introduced to Al Muhajiroun, a group led in Britain by Omar Bakri Mohammed, in his neighborhood in West Sussex. The group indoctrinates followers in the virtues of an Islamic state and indoctrinates a strict code of personal behavior. It expects members to shun friends who do not practice strict Islamic mores.  On the political side, Mr. Khyam calmly told the court about how he watched bloody videotapes of Russian soldiers blowing up mosques in Chechnya, and of atrocities by the Serbs against Muslims in Bosnia, which were shown to members of Al Muhajiroun.  But he soon tired of Al Muhajiroun, he said, and yearned for something more than the group’s desire for an Islamic state in Britain, which he deemed to be “not realistic.”  He took his first trip to Pakistan as a vacation with his mother and his brothers in 1999, when he was just a teenager. There, he experienced firsthand what he had heard about at home: the cause of Kashmir, the border area claimed by both Pakistan and India. He met with a group, Al Badr Mujahedeen, that fought, he said, to free Kashmir from Indian control.  In early 2000, Mr. Khyam was back in Pakistan. He found a training camp for fighters being sent to Kashmir that was run, he said, by Inter-Services Intelligence.  According to his testimony, the American-led war in Afghanistan, and later Iraq, dramatically colored his views. Those wars, he said, were wars against Islam, and he hoped to join the fight.  “By this time I had a lot of contact with the I.S.I. because of my family,” he said, referring to the Pakistani intelligence service. He visited the headquarters of the agency in Islamabad, and was told that what the Americans wanted “is to stop anyone who calls for the return of an Islamic state or a caliphate.”  From 2002 on, Mr. Khyam said he shuttled between Britain and Pakistan, culminating in a trip in 2003 to a training camp in Malakand in the North-West Frontier Province with five of his fellow defendants, including his younger brother, Shujah, who was acquitted.  By late 2003, according to prosecution evidence, Mr. Khyam had decided from his trips to Pakistan to concentrate on a plot in Britain that would involve a fertilizer bomb.  Mr. Khyam, using some of the organizational skills he had honed as a young man at home, can be heard on surveillance tapes divvying up responsibilities for the plan.  Along the way, he found time to marry — in what he called a “religious marriage” — Saira, a Pakistani woman.  They finally married in a civil ceremony on March 25, 2004, and a few days later, Mr. Khyam was arrested by the police in a bedroom of a Holiday Inn in England while he was on his honeymoon with his wife.
Citing recent terror plots, U.S. officials want to curb the access of British citizens of Pakistani origin to America.