Throughout most of the Thatcher years, the Labour Party was consistent about one thing: the Prevention of Terrorism Act, as was, had to repealed. IRA active service units were active indeed. The cities of England - Scotland was a peculiar exception - were under constant threat. But the PTA was judged by Labour to be an abomination, the antithesis of the rule of law, and of everything - such was the irony - it was designed to protect.

Where are we now? We are in a country that regards the enactment of fresh "anti-terrorism legislation" as an annual event. We are in a world in which John Reid, a soon-to-be superannuated home secretary, bellows at judges for both upholding the constitution and law itself. We are in a place in which derogation from the European Convention on Human Rights - woven into the law of the land, as it happens, by Labour - is threatened as a necessary security measure.

Why? Because Dr Reid says so, for reasons Dr Reid is unwilling to explain. The threat is vast, he says, and unremitting. It would chill your blood to know what John Reid knows. But Reid, departing a great office of state with all the grace he has brought to the position, will not tell you what he knows. Trust him on that.

Our world is shaped, daily, by action and reaction. The London Tube bombings told most of us all that we need to know about the far shores of radical Islam. Our society has been nominated as the enemy of a baleful god. Our decadence confirms the intent of our foreign policy, and vice versa, in the minds of suicidal killers who prefer a perverted concordance to the Koran itself. Yet the war is real enough, and no sane person doubts it.

We value our security. We pray for aid and safety. So we elect people - this is one of our distinguishing traits - to maintain the social contract. In return, we find ourselves with a government inching steadily towards a remarkable proposition, without precedent in two-and-a-half centuries.

They are close, very close, to saying this: there is no such thing as a human right.

Historians will tell you that the very concept is novel. They will remind you that during the twentieth century's great cataclysms the "defence of the realm" became an overriding concern, supplanting all British liberties. Those who lived through the last war still remember their identity cards. But they also remember a Britain that disposed of such state controls at the first opportunity. Your identity - and how's this for a right? - was your own affair.

Not any more. Thanks to a threat less potent than that mustered by the Provisional IRA in a slow year, we find a Prime Minister deriding law, judges and the bleeding hearts - your servant - who worry over liberty and executive power. Tony Blair tells us that still more police powers are needed, whatever the police might think; that privacy is no longer a human right; that the civil liberties of the suspect - or the duties of a judge - are an impediment to our security.

Last week, thinking aloud, Reid suggested that the exercise of the right to silence could in future be "interpreted" by courts as a mark of intent (the common word is guilt).

This week, Blair, laying traps for his successor, has espoused a revival of the old, disreputable sus laws (which gave police powers to stop and search on mere suspicion of crime). If the disappearing prime minister and a Home Office stooge named McNulty have their way, withholding your identity or refusing to answer police questions will become a criminal offence, liable to a £5000 fine.

You need not have done anything wrong. Officers need not mention reasonable suspicion. The proposed law may create, as the Northern Ireland secretary, Peter Hain, felt obliged to confess at the weekend, "the domestic equivalent of Guantanamo Bay". But what the hell. If - cling to that qualifier, you may need it one day - "you've done nothing wrong you have nothing to fear". If you put your privacy above the security of your fellows you are clearly guilty of irresponsibility. And if you do not recognise the world you are allowing, tough luck.

This is the most surveilled - apologies for the grotesque verb - society in the western world. Anonymity, discretion, a private life are no longer permitted. We have cameras like a voyeurs' orgy on every village lamppost and a data file for every subject in every Tesco. We will shortly endure identity cards, bio-specific plastic parasites to match our store cards, without which ordinary life will become impossible. Loyalty, then, with bonus points, for all. And will we be more safe?

I remember the sus laws of a previous age. No problem for me, back then, even as a tourist on Brixton's old "front line": I was white. Somehow, that piece of genetic magic never seemed to fail. But Brixton still went up, Toxteth went up; some of my contemporaries decided that harassment needed to be answered with maximum harassment.

Home secretaries, commanding the special patrol groups, duly deplored the entirely needless violence. Of course.

When Blair takes another bite from our liberties in the pages of a Murdoch paper, therefore, take it as guaranteed: another couple of dozen young Muslim men have just had their paranoia confirmed. As a consequence, another Tube train is at risk. Iraq may have become a kind of virtual conflict, a theoretical construct droning away as a sub-text to the nightly news, a cause for arguments and an excuse for rhetoric. It is, still, a small country, far away, of which, inexcusably, we know little. This assault is different.

If and when the coppers start halting young men on the streets simply because their skin is darker than average Blair and Reid will have their crisis. They will not be around to answer for it - strange timing, or perhaps not so strange - but the war, a real war, will have become generational. True threats to our security will become subsumed into a larger, inchoate unease: us and "them".

We are assured that the Scottish Executive will refuse "stop-and-question" powers for the police under its control. That would be rational. Since when was a police officer unable to stop me, or you, and ask questions? So much is also true, it so happens, in England and Wales, hence the bafflement of unnamed chief constables who wonder, apparently, what Blair and Reid are on about. I'm guessing, but the cops probably know more about politics than they are prepared to say.

The state, our state, is gathering power to itself. Scotland's government may propose to resist, but its record of preventing Home Office attempts to kidnap child refugees is not encouraging. We'll see.

For now, political anoraks are invited to wonder why Blair and Reid are making quite such a fuss in their remaining weeks in office. The rest of us can only examine what we mean, exactly, by liberty.

Are we under threat? Probably. Are we more safe, thanks to our implacable new Labour guardians? I doubt it. Are notions of rights and due process at risk? Unquestionably. Are we losing sight of the freedoms we claim to live by?

I fear so. No hyperbole: I fear.