Several of the young men arrested in Britain are believed to have been in contact with Khan. One -- a man known by the alias Abu Eisa Al-Hindi -- was alleged to be the head of Al-Qaeda operations in Britain and was believed to receive his orders directly from Osama bin Laden.
Magnus Ranstorp, the director of the Centre for the Study of Terrorism and Political Violence at the University of St. Andrews in Scotland, says Al Hindi and others are believed to have ties to grave terror plots in the U.K. -- including a plan to launch an attack on London's Heathrow Airport: "There is a serious threat. We've had reports of different types of plots against public targets -- particularly transport targets. With these latest arrests we saw the security being elevated around Heathrow. There have been previous plots discovered, so the authorities have to take this information by the [British Security Service] MI5 or the New Scotland Yard, or by external security services very seriously."
Some observers worry these latest arrests risk sparking a further rise in hostility among the country's Muslims, who have complained of growing anti-Islamic bias on the part of the British public and law enforcement officials.
But Inayat Bunglawala, the spokesman for the Muslim Council of Britain, says most Muslims still support the police in their fight against terrorism: "The police force have an enormously difficult task on their hands trying to secure this country from the very real threat of terror. After the Madrid bombings in March this year there is no room for complacency, and we fully understand that the police have a necessary job to do."
Some of the men arrested have since been released. But the government now wants to extend the two-week maximum custody limit for the remaining detainees in order to enable the police to pursue further interrogations.
The decision is likely to raise objections among many British Muslims. Bunglawala says new antiterror laws and high-profile arrests have left many Muslims worried about rising anti-Islamic sentiment: "To date, over 609 people have been arrested, and that, of course, gets blanket [media] coverage. Only 15 people have been convicted of any actual offenses -- it's a strike rate of 2 percent. And when these people are released it gets nowhere near the same level of publicity. So, the impression left in the minds of many of the British people is that there are literally hundreds of Islamic so-called terrorists running around in this country. And that has done an enormous damage."
Ghayasuddin Siddiqui of the Muslim Parliament is even more concerned, not only about bad publicity, but also about the lasting effect of Britain's new antiterrorism laws -- legislation which he says should be eliminated: "I think this has gone too far, and the time has come that the whole chapter [should be] closed. Otherwise, the Muslim community -- especially the young people -- could react in a very, very negative way, because they've been just simply criminalized."
Bunglawala says the police "often act in haste" and arrest people despite a lack of evidence.
For example, 10 people were arrested in Manchester in April, allegedly plotting to blow up the Manchester United soccer stadium and a nearby shopping center. They were later released without charge, but the police made no apology.
"I think it is right that the police relook at the intelligence they are using, and make sure they are not just acting on some malicious tip-offs, that they are acting on credible intelligence," Bunglawala said. "Because otherwise, many Muslims -- whose help is necessary to win this battle against the terror threat -- may well refuse to come forward to help."
The police acknowledge the problems of acting prematurely. Magnus Ranstorp says most law enforcement officials face a difficult decision -- do they act quickly and risk possible harassment of innocent citizens? Or do they do whatever they can to fight the terrorist threat?
"It's always a dilemma, and I think the police are very, very cognizant of this and the necessity to balance the demand for security in a changing security environment after 9/11 with upholding civil liberties. I think the important thing is to have judicial oversight, the judicial process, where the rights of the defendant can be voiced," he said.