If you haven't seen David Davis' brilliant resignation speech yet, you should click below to watch it. In the wake of the commons' vote to extend pre-trial detention without charge to 42 days, Davis has resigned as Shadow Home Secretary and quit Parliament, and will now fight a by-election purely on the issue of civil liberties.

This is a remarkable display of political courage, and it is wonderful to see a politician take a real stand on a matter of principle. In the short-term, this may not be a wonderful development for his party, with some in the media unfairly characterizing it as the product of internal strife. But regardless of party politics, Davis' decision put the current government's appalling record on civil liberties directly to the public could not be more welcome.

Davis is not just standing on the issue of detention without charge, but against a whole raft of illiberal policies, from restrictions on free speech, to surveillance, ID cards and the database state. With luck Davis' 'nuclear option' could mark a turning point in the national debate.

Winston Churchill once campaigned under the slogan "Set the people free!" David Davis could do worse than adopt the same rallying cry.