Rules that would guide the deportation of alleged terrorist sympathisers were published by the government last week. It is a key part of their attempt to deal with the "evil ideology" of Islamism and its role in inspiring terrorist attacks on our country. But there is growing unease about whether this response is right or will be effective in stopping future attacks. There is an even more serious fear that we might be making the situation worse.
This is exactly what happened in the reaction to the attacks on America in 2001. For years after 9/11 we were told that we faced a powerful, well-organised enemy, who had established a centrally coordinated command structure that needed to be sought out and crushed. We went storming into Iraq to prevent a rogue state from supplying WMD to this organisation. This would make the world a safer place. But the enemy was not an organised network, and going into Iraq has done the opposite of what we intended. Our actions have inspired resentment throughout the Middle East and Iraq is now the world centre of terrorist activity.
Last year I made a series of documentaries for the BBC, The Power of Nightmares,
which showed how a fantasy image of the "al-Qaida" organisation was created. The films told how the response to the shocking events of September 11 2001 swung out of control, and the threat became exaggerated to a dangerous level. Although there was a serious terrorist threat, the films criticised the apocalyptic vision of what lay behind it - the "nightmare" of a uniquely powerful network, unlike any previous terrorist danger and capable of overwhelming our society and our democracy.
The Power of Nightmares said bluntly that this was a fantasy. The real threat came not from a network, but from individuals and groups linked only by an idea. Our energies were going into fighting a phantom enemy. We were looking for a network that didn't exist when we should have been dealing with an idea that does.
The evidence we have of what lies behind the London bombings confirms that this was the real nature of the threat. It is fascinating to see how suddenly all the terror "experts" have changed their tune. For three years they told us breathlessly about a terrifying global network. Now, suddenly, it has gone away and been replaced by "an evil ideology" that inspires young, angry Muslim males in our own society.
It is good that we now all agree on the nature of the threat, but there remains a danger that the "idea" will be simplified, exaggerated and distorted just as the "network" was, and that in this mood of fear the government will bring in policies that will alienate young Muslims further and drive them towards dangerous extremism.
Modern Islamism is a complex political movement with a history that goes back more than 50 years. Its most influential ideologist was an Egyptian school inspector, Sayyid Qutb. In the 50s he wrote a series of books that put forward a powerful critique of modern western culture and democracy, and called for a new type of utopian society in Muslim lands in which Islam would play a central political role.
Out of this has come a movement for revolutionary change in the Islamic world that includes an extraordinary range of groupings and variations on Qutb's original arguments. It is only a tiny minority in the Islamist movement who have developed these ideas into a politics that advocates terrorism against the west. Historians of Islamism have shown that this minority, grouped initially around Osama bin Laden and Ayman Zawahiri in the late 90s, turned to attacking the west only because of the failure of the wider movement to achieve its revolutionary aims in the Muslim world.
We must be aware of this distinction so as to avoid a witch-hunt against the whole Islamist movement. We may not agree with its reactionary vision of the political use of Islam and the pessimistic, anti-progressive beliefs that lie at the heart of Qutb's teachings, but it is essential to realise that there is no inherent link between these ideas and terrorism. There are worrying signs that journalists are confusing the murderous beliefs of a genuinely destructive minority with the political ideas of a much wider movement. By lumping Islamism into a frightening, violent, anti-western movement led by the "preachers of hate", they risk exaggerating and distorting the threat yet again.
The real danger is that, by suppressing Islamism, we will make its ideas more attractive to already marginalised young men. In the process we may inadvertently drive them further towards the extreme militant wings of the movement, and prove yet again the old adage that the real threat to democracy from terrorism is not the action but the reaction.
· Adam Curtis wrote and produced The Power of Nightmares: the Rise of the Politics of Fear, which was broadcast on BBC2 last October
adam.curtis@bbc.co.uk 
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