If you have ever attended an event about counter-terrorism, you will have experienced the inevitable, interminable and insoluble debate about what the word 'extremist' means. It is usually accompanied by some guff historical commentary: that the Suffragettes were once considered extreme, and so were the Abolitionists et cetera. Even though I've never been to a terrorism event where it hasn't been raised, for some reason the instigator of this lurch usually believes he or she is the first person to have thought of it.

This happened to me twice this past week. Obviously it is important to be clear on terms, and thought ought to be given to words that carry implied moral judgments. Unfortunately, trying define extremism through historical analogy or linguistic acrobatics is usually impossible. Most worrying, though, is the tendency to give up in the face of this conceptual confusion, concluding that perhaps extremist ideas are not that bad, as they might be tomorrow's established political truths - just like the Suffragettes'.

This is not just an academic exercise. Deciding who is and isn't an extremist is important when setting counter-radicalisation policy, because on the whole the government ought not work with extremists. It is an issue that still divides the coalition. Some clarity is needed, and this is my attempt at providing a little.

The predicament lies in the word itself. Extreme denotes a position relative to a non-extreme equivalent. The error is to equate the non-extreme centre-point with the dominant or ruling political establishment of the day. It is said that Tony Blair, plotted on a public opinion political spectrum, sits dead centre. Therefore an extremist ought to be defined according to how far they are from Mr Blair. This is nonsense of course.

Instead, an extremist view should accord to one's view of individual's human and civic rights, which is the cornerstone of living in a liberal democracy. My simple definition of extremism would be: groups or individuals that oppose or undermine the democratic and human rights of British citizens. True, over time even our notion of these might change (although I hope not), and of course this definition has flaws. But if we are to use the word (and we will), it makes sense to make it in relation to a set of ideas which are broadly agreed to be of moral and legal significance.

This allows for a number of things. First, we can dispense with discriminatory efforts at defining extremism in relation to certain (usually Islamic) views. This definition is ideology blind. Second, it allows that the mainstream can sometimes be extreme. Third, it limits the use of the word by politicians to lazily discredit any group they do not like.

But most importantly, it jettisons useless historical comparisons which conclude that groups like Hizb ut Tahrir - who seek to undermine certain citizens' rights - are no worse than Suffragettes, who sought to uphold them. Yes, the Suffragettes were considered to hold extreme views in their day - but by today's definition they certainly would not. This way, we avoid getting trapped in a cul-de-sac of relativism in which every group opposing the ruling power - democracies or despotism - are of equal moral value, which they are not. And as a bonus, the coffee break might be on time at your next counter-terrorism conference, rather than 45 minutes late.

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