A former British Jihadist:

[W]hat drove me and many others to plot acts of extreme terror within Britain and abroad was a sense that we were fighting for the creation of a revolutionary worldwide Islamic state that would dispense Islamic justice.

If we were interested in justice, you may ask, how did this continuing violence come to be the means of promoting such a (flawed) Utopian goal?

How do Islamic radicals justify such terror in the name of their religion?

There isn’t enough room to outline everything here, but the foundation of extremist reasoning rests upon a model of the world in which you are either a believer or an infidel.

Formal Islamic theology, unlike Christian theology, does not allow for the separation of state and religion: they are considered to be one and the same.

For centuries, the reasoning of Islamic jurists has set down rules of interaction between Dar ul-Islam (the Land of Islam) and Dar ul-Kufr (the Land of Unbelief) to cover almost every matter of trade, peace and war.

But what radicals and extremists do is to take this two steps further. Their first step has been to argue that, since there is no pure Islamic state, the whole world must be Dar ul-Kufr (The Land of Unbelief).

Step two: since Islam must declare war on unbelief, they have declared war upon the whole world.

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For decades, radicals have been exploiting the tensions between Islamic theology and the modern secular state - typically by starting debate with the question: “Are you British or Muslim?”

But the main reason why radicals have managed to increase their following is because most Muslim institutions in Britain just don’t want to talk about theology.

They refuse to broach the difficult and often complex truth that Islam can be interpreted as condoning violence against the unbeliever - and instead repeat the mantra that Islam is peace and hope that all of this debate will go away.

[...]

Because so many in the Muslim community refuse to challenge centuries-old theological arguments, the tensions between Islamic theology and the modern world grow larger every day.

I believe that the issue of terrorism can be easily demystified if Muslims and non-Muslims start openly to discuss the ideas that fuel terrorism.

Crucially, the Muslim community in Britain must slap itself awake from its state of denial and realise there is no shame in admitting the extremism within our families, communities and worldwide co-religionists.