The terrorism legislation outlined in the Queen's Speech yesterday won't have been influenced by the remarks made by Jonathan Evans, the head of MI5, the day before. Yet in revealing that British teenagers are being groomed to become terrorists, Mr Evans has helped prepare the ground that makes changes to current terrorism legislation seem necessary.

As someone who once lived by Islamism – the ideology adopted by, though not exclusive to, Jihadists – I can understand what would radicalise a young British Muslim. Sadly though, the state of debate at the moment is one more determined by politics than it is by a need to get to the root of the problem. Two camps have emerged. The first camp exclusively blames this development on government policy, both foreign and domestic. The second exclusively blames Islamism, and tends to hide a deeper animosity for Islam itself.

I believe that it is not one or the other. A more nuanced approach – based on an understanding of the Islamist psyche – is needed to get to the root of radicalisation. Islamism is a modern ideology masquerading as an ancient religion. As such it shares a common trait with many other constructed ideologies. This trait is its fundamental, theoretical justification for change regardless of circumstances. Ideologies do not merely provide "solutions" to perceived problems, they provide a framework within which to define problems in the first place.

By doing this they effectively "discover" problems where there may be none, and can act as an obstacle to solving other problems when the solution doesn't fit certain dogma. Islamism is formed by superimposing certain Western political paradigms onto the religion of Islam. The absence of such modern Islamist notions in Muslim political systems and society is subsequently equated to the absence of Islam itself. Whatever institutions are found in place are subsequently described as Kufr (based on disbelief), which must be overthrown as a religious obligation.

Herein lies the problem. Islamism is not driven by a sense of material injustice in this life. It is driven by an ideological agenda that will seek change regardless of such material injustice. For Islamists, the absence of Islamism is itself the injustice. All man-made legislation is oppressive, and only divine legislation can liberate man from such oppression. Any material problems, such as poverty, crime or conflict, are hence not primary reasons for the Islamist revolution, they are but convenient recruitment tools used to further destabilise those who rule by man-made legislation.

If the very same social problems were to occur in an Islamist state, good Muslims would be counselled to exert patience and turn to their government for solutions. Hence, revolutionary Islamists and in particular Jihadists are opposed to all regimes in the Muslim world as a point of principle, whether such systems are representative or not.

On the other hand, the vast majority of Muslims are not Islamists, and even fewer are Jihadists. So how are the minority of Muslim youth attracted to such an ideology? The factor that stands out is the way in which radical Islamism grew in popularity alongside extremely bad policy decisions made by governments, including our own. It is no coincidence that the Soviet occupation of Afghanistan acted as a catalyst for Jihadism, just as our occupation of Iraq is now doing the same. It is also no coincidence that there were no Jihadist attacks on British mainland before the fateful invasion of Iraq. Our government's pre 9/11 support for dictators in the Muslim world, including Saddam Hussein, assured this country's unpopularity amongst those who suffered under such tyrants. As Islamism and Jihadism rose globally, so did the way in which governments cut back on fundamental civil liberties. The state of our own country's terror laws are a case in point; profiling, control orders and detention without charge are all now an ordinary part of our legal mosaic. Terrorist profiling has reached such a level of absurdity that a Muslim minister of our own government was last week detained at a US airport under terrorism procedures. If the "Black Widows" – secular Chechen female suicide bombers – should teach us something it is that terrorists have no profile.

My point is that the vast majority of these measures do not affect terrorists, they aid them in their cynical use of events for ideological ends. What was once mere Islamist and Jihadist propaganda, that non-Muslims hate Muslims, is now less easy to discredit for young minds. Polarisation only serves those, on both sides of the debate, who seek war. The ordinary Muslim suffers, and in turn becomes angry. This anger unintentionally breeds an atmosphere where alienated young Muslims, still maturing in the ways in which to deal with anger, are susceptible to ideologically driven recruitment by Islamists and Jihadists.

Such an analysis requires a two-pronged approach. Islamism needs to be ideologically challenged by those equipped to do so. Vitally though, policy matters must also not be ignored. If we stop granting them fodder, it will be harder for them to recruit. It is in this light that I stand opposed to the new Counter- Terrorism Bill, just as I stand opposed to Islamism.

The writer is a former leadership member of Hizb ut-Tahrir, for which he was imprisoned for four years in Egypt