It all began with the men in white coats. No, they weren’t the psychiatrists who come to take you away when you go crazy. But you might well think that 20,000 people must be mad to pay good money to watch a game so slow that a single match may last five whole days. I am talking about cricket.

To the uninitiated, the laws of cricket are a mystery more unfathomable than the Dead Sea Scrolls, the Oracle of Delphi, and the human genome put together. The white-coated high priests of cricket who interpret these arcane rules are, as in baseball, the umpires. International games are known as Test matches, and this summer Pakistan has been here to play a four-match series against England. On Sunday afternoon, the last of these leisurely duels was drawing towards what for cricketers passes for a climax. Pakistan was bowling with deadly accuracy, England was making their last stand, and an exciting finish was in prospect.

This sporting idyll was rudely interrupted when an entirely foreseeable though unforeseen incident abruptly transformed the Oval, hitherto the second most hallowed cricket ground in the world, into a new battlefield in the war on terror.

The umpires — one West Indian, one Australian — decided that the Pakistan team had been guilty of “ball-tampering.” This is not an exotic practice from the Kama Sutra, but a form of cheating, involving scratching the leather ball in such a way as to affect its behavior when hurled at well over 100 mph. England — who remained innocent bystanders throughout — was awarded five runs as a penalty, the first time that this relatively new rule had been invoked in a Test.

The Pakistanis protested their innocence. Their numerous British Muslim supporters in the crowd started to get angry. Other spectators were simply frustrated by the lack of play.

At this point, tea was served. Tempers ought to have been calmed by copious quantities of a drink as familiar on the Indian subcontinent as in England. When the tea interval ended, and the England players returned to the pitch, their Pakistani opponents protested. They refused to come out of their dressing room — one player ostentatiously sat on the balcony, reading a newspaper.

Now it was the umpires’ turn to get angry. Having warned the Pakistanis of the consequences if they refused to stop sulking in their tents, they awarded the match to England. By now millions of people, watching on television around the world, had become aware that something extraordinary was happening. Nothing like this had ever happened before in a Test match.

At this point, politics began to kick in — or, to be more precise, political theology. Muslim pride had been wounded. Pakistan — not just the cricket team, but the entire nation, including the President, General Musharraf — accused the Australian umpire, Darrell Hair, of bias. Sports commentators unhelpfully reminded everybody that Mr. Hair had been involved in disputes before not only with Pakistan but also with India and Sri Lanka. They omitted to point out that he had also had disputes with non-Asian teams. Nobody was quite sure what Mr. Hair was supposed to be biased against — was it race or religion? — but that he was biased was simply assumed, not only by the Pakistanis, but even by the British press. Imran Khan, a cricketing celebrity-turned-politician, accused Mr. Hair of being a “mini-Hitler” — an unwise accusation, given that Pakistan is still a military dictatorship. The dispute is now in the hands of the officials and, inevitably, the lawyers. The umpire himself refused to strike back. “Life goes on, Mr. Hair said. “Nobody died.” Not yet.

In normal times, a row about cheating in sport would not spill over into politics. But these are not normal times. This week, eleven British Muslims were charged with conspiracy to murder thousands of passengers on several transatlantic airliners, a similar number are still being questioned. A huge nationwide investigation is continuing: 69 houses and other buildings have so far been searched, revealing “martyr” videos, bomb-making equipment, and vast quantities of incriminating data. Two more British Muslims have been arrested in Pakistan. Most of the suspects have Pakistani backgrounds, and some are alleged to have visited Pakistan recently.

The discovery of this plot prompted the biggest security alert in the history of transatlantic aviation, the effects of which are still being felt by countless travellers on business or vacation. Many people are suspicious of Muslims, many Muslims are suspicious of the authorities, and everybody expects a terrorist attack sooner or later.

In these circumstances, the cricket dispute has served to exacerbate Muslim paranoia.The members of the Pakistani team are, to a man, devout Muslims. They are seen as heroes by the increasingly Islamist youth here in Britain. Many young Muslims react to a suggestion of cheating in the same way that they react to allegations of terrorism: they simply deny it. The umpire is always right, it seems, except when he finds Muslims to be in the wrong. Solidarity takes precedence over truth. A Muslim’s allegiance, they insist, is to the ummah, the global Islamic community, rather than to the non-Muslim country in which he or she happens to live. Anyhow, they say, the West is at war with Islam, and sport is merely a continuation of war by other means. This belligerent attitude to the West is, of course, a self-fulfilling prophecy, but it is gaining ground.

We talk blithely about British Muslims, but the truth is that Britain is becoming a microcosm of the ummah. One of the most striking things about the latest conspiracy is the involvement of Muslim converts, including the white middle-class son of a Conservative party official and an Afro-Carribean former Rastafarian.

New figures out this week reveal that over the last decade Britain has absorbed by far the largest wave of immigrants in its history, including at least a million from outside Europe — a large proportion of them from Islamic countries in North Africa, the Middle East, and the Indian subcontinent. It is obvious that the official figure of 1.7 million Muslims is a gross underestimate. In parts of London, up to half of all residents were born abroad, and many of the rest are second or third generation. There is now a pool of itinerant Muslims across Britain, many of them unknown to the authorities, in which terrorists can swim.

As well as rogue states that sponsor terrorism, such as Iran and Syria, there are others that act as incubators of terrorism. Pakistan, like Saudi Arabia and Egypt, has long been one of these incubator states. European countries with large Muslim minorities have become incubators only recently, but the eggs are starting to hatch.