That elementary measure was also a piece of blatant hypocrisy from the British government. For at least a decade, and possibly much longer, it had been covert British policy to provide, in Britain, a safe haven for radical Muslim terrorists to "finance, plan, support or commit terrorist acts".

That is why Abu Hamza - who was finally convicted of incitement to murder last week on the basis of evidence most of which was at least seven years old - was allowed to operate for so long from his mosque in Finsbury Park. It is also why the British government consistently refused requests to extradite known terrorists, not just from Egypt, Saudi Arabia, the Yemen and Jordan, but also from our neighbours in France. To the understandable fury of the French and many of the governments in the Middle East, Britain knowingly haboured and protected some of the most dangerous Islamic fundamentalists in the world.

To give just three examples: the plots to plant bombs on the Paris Metro in the 1980s and 1990s were hatched in London; so was the assassination of General Massoud in Afghanistan, days before the 9/11 outrages; and so was the kidnapping of Western tourists in Yemen. The government and security services knew what was happening: they were frequently alerted by pleas for action by increasingly desperate foreign governments. But they chose to allow the fanatics to continue their deadly activities.

It is difficult to understand the thinking behind this transparently self-destructive policy. The idea seems to have been that if we left Islamic fanatics free to plot terrorism here, they would reciprocate by not blowing up people in Britain. The short-sighted stupidity of that policy was definitively demonstrated by the deaths of more than 50 people on July 7 last year.

MI5 must bear the brunt of the blame for it. Constitutionally, the Director General (DG) of MI5 has the power to determine who counts as a threat to British interests: the DG cannot be ordered by the Prime Minister to consider a particular group or individual a threat. During the 1990s, the then DG decided that Islamic fundamentalists plotting terrorism in London and other British cities were not a real threat to Britain. MI5 wound down its "international terrorism" desk, on the grounds that Islamic terrorists in Britain were considered a threat only to other countries - and it was no concern of ours if they exploded bombs in foreign cities.

The resulting lack of intelligence on the activities of Islamic radicals meant that there was insufficient evidence to bring prosecutions. When the police, acting independently, began to realise the alarming nature of what some of the fanatics, Abu Hamza included, were doing, the Crown Prosecution Service insisted that there was "no realistic chance of conviction".

MI5's covert pact with the terrorists resulted, as all such pacts do, in them breaking their side of the bargain. There is, however, a disturbing echo of that hopeless pact in this Government's present policy towards radical Islam. It can be seen in their cringeing reaction to the violent protests over the Danish cartoons of the Prophet Mohammed. Instead of joining most of the rest of Europe's leaders in robustly defending the right to free speech, and attacking the fanatics who have threatened to "behead those who insult Islam", Jack Straw, the Foreign Secretary, has gone out on a limb and said that the publication of the cartoons was "unnecessary, insensitive, disrespectful and wrong".

Those remarks reflect the thinking behind MI5's shameful policy: if we are "nice" to radical Islamists, they will be "nice" to us. But the belief in the possibility of a deal with radical Islam is totally wrong. Islamic terrorists are prepared to kill and maim innocent people precisely because they are not interested in any kind of "deal". The only way to defeat the extremists is to isolate them from the peaceful majority of Muslims in Britain, and combat their horrible ideology of death directly.

Will the Government do that? This week sees votes on its new Terrorism Bill, and the Bill to introduce identity cards. The Government insists that support for those laws is a litmus test of our determination to confront terrorism. It is not. There are already enough laws on the statute books to tackle Islamic terrorism. The Government has not been prepared to use them. Only by confronting the radical Islamists head-on, and forging a united front with other European nations to defend the values of a liberal and tolerant society, can we defeat the extremists. The problem is that this Government has not yet proved willing to do it.