You think the intensity will never fade – but it does. Just after the July 7 tube bombings we were all so alert. We all looked around every tube carriage we entered, stared at everyone carrying a rucksack, worrying about people fidgeting with cables (Walkman? IPod? bomb?). Vigilance fades. The atmosphere is nowhere near as tense as it then was. But the threat is still here.

And let’s be clear. I don’t want to die. I certainly haven’t finished annoying my children as yet and look forward one day to aggravating them further by offering them my advice on how to bring up their children – should they ever produce any. So I welcome the Government’s Terror Bill that began its journey through Parliament this week.

Much of the proposed legislation is a no-brainer – for example making an offence of going to a terrorist training camp or being found preparing a terrorist act. But there is one part of the bill that seriously worries me. And the way Parliament works, most of the time you have to vote for or against the whole package – passing everything or rejecting it all. Both of these outcomes would be highly unsatisfactory as the legislation stands at the moment.

The Government had to back down on one of its proposals before publishing the Bill – to make an offence of ‘the glorification of terrorism’. It was so woolly, so undefined – one man’s freedom fighter being another man’s terrorist.

It would be easy to legally define Nelson Mandela as a terrorist (remember when the ANC believed in bombs and the armed struggle?)- and so catch out any who praise him. Which makes the point that blanket, poorly worded definitions catch all sorts of people other than those intended who we might all agree should be the targets of legislation.

This leaves the big remaining problem – the Government’s determination to change the rules about holding terror suspects without charge from 14 days to 90 days. They are now trying to move the goal posts by saying that a judge must have oversight and the police will have to request continuation of such an extension every seven days.

Detention without charge strikes at the heart of the principles of the British justice system. This isn’t though about vague legal principles or nice warm words – it’s about whether ordinary people can be locked up even if there isn’t enough evidence to bring them to trial. That should only be done in the most extreme of circumstances for the shortest possible period.

Of course the authorities always say they really know X is dangerous – but then they really “knew” there were weapons of mass destruction in Iraq didn’t they? Just as they really “knew” the Birmingham Four, the Guildford Six and Judith Ward were guilty. Only one small problem – they weren’t guilty of the terrorist acts the authorities “knew” they’d done. They were innocent. And while innocent people were locked up, the guilty were left roaming free.

Now whilst the police are doing a truly extraordinary job in terms of keeping us safe – particularly in London where the attacks took place – it is in the nature of policing to want more powers. And it is in the responsibility of politicians to ensure that the powers granted are appropriate – not simply automatically agree.

There are other, far more legitimate ways a suspected terrorist could be detained if the police feel they need more time than 14 days. For example, people could be charged with a lesser offence – such as the new one of acts preparatory to terrorism, while evidence is being gathered for other charges.

Far too often the Government take the soft option of talking tough and introducing legislation – curbing liberties as a first choice, not a last resort. They talk the talk about extreme circumstances, great care, carefully supervision and on and on, but we end up with the farcical absurdity of an old man being held under anti-terrorism legislation for shouting one heckle at a Labour conference. What would they have done if he’d dared heckled twice … ?