'Knowledge without integrity is dangerous and dreadful." This sentiment, one of many fine observations in Samuel Johnson's Rasselas, remains as excellent and true as it was on its publication.

So sensible and of such continued relevance, in fact, that it was used 250 years later to introduce a policy paper from the Conservative Party.

Admirably entitled "Reversing the Rise of the Surveillance State", this short paper by Dominic Grieve and Eleanor Laing, then respectively the Shadow Justice Secretary and Shadow Justice Minister, is full of good sense about the dangers of governments maintaining huge databases on the population.

It argues convincingly against such surveillance on three principal grounds: it is an offence against privacy and an assault on civil liberties; it is incredibly expensive and excessively bureaucratic; it is unlikely to work, and even if it did, would not achieve its stated aims.

The empirical truth of these observations is as plain as the nose on your face. Indeed, I will go further – they are as plain as the nose on my face. Even though this paper was produced by the Tory party, everyone could see that it had hit the target whang in the gold. Nobody could possibly disagree with its findings except David Blunkett, Charles Clarke, John Reid, Jacqui Smith and Alan Johnson.

Until now, unfortunately. Theresa May, currently Home Secretary in succession to that ignominious roll call of would-be Stasi impersonators, seems to have performed a volte-face on the one area of Conservative policy which everyone with an interest in, on the one hand, civil liberties, or on the other, proportionate, cost-effective governance, applauded.

It's one of those moments when we may have cause to be grateful that it's a Coalition Government, since the Liberal Democrats are loudly, and correctly, pointing out that the proposals to maintain a record of everyone's emails, webpage visits and other internet traffic are fundamentally illiberal and undemocratic. Before they rush to take the credit for the fact that the Government has backed off a bit and says these will now be only draft proposals, it's worth noting that many Conservative backbenchers are also very strongly opposed to such measures – because they are, of course, fundamentally unconservative as well.

By that I mean that they are exactly opposed to the dominant themes of conservatism: the defence of individual liberty, insistence on the rule of law and opposition to the expansion of state power and expenditure. Those who take the position that "if you have nothing to fear, you have nothing to hide" do not belong in the tradition of Hume, Burke, Acton and Oakeshott, but on the side of statist authoritarians like Stalin, Mao, Honecker and Ceausescu. It's the bit that's wrong when it calls itself the Right.

The defence of the Blairite and Brownite home secretaries (besides their assumption that the state ought to intrude into every area of life) was that such measures were an essential response to threats posed by terrorism. Of course they would be directed only at those who planned terrible atrocities. No-one would dream of using them, for example, to extradite alleged hackers or copyright infringers to the US, or keep an eye on peaceful political protesters, or police those with religious views at odds with equality and diversity legislation. Heaven forfend.

Subsequent events do not lend this assurance much credibility. If surveillance were to be directed solely at terrorists, there have always existed perfectly good means for implementing it. It may be a nuisance for the police and the security services that they include such impediments as reasonable grounds for suspicion, obtaining court orders and producing evidence in front of a jury before you lock up your suspects, but that's what makes the United Kingdom different from Saudi Arabia, or China, or Somalia. Countries where those who use the "nothing to fear, nothing to hide" argument may note that what might cause you fear and give you a reason to hide could be membership of a church or your sexual orientation.

In any case, the point of terrorism is not just to kill people; more die on the roads than because of Islamist bombs, after all. The clue is in the name. Terrorism's purpose is to cause terror and, in so doing, to alter substantially the way in which people go about their business, to cause fear and inconvenience and to erode the way of life which it seeks to oppose. And if those are its objectives, the defences raised by Western governments in the name of the "war against terror" have struck more effective blows than anything devised by al Qaeda bombmakers.

But if electronic surveillance is counter-productive because it undermines a free society, it is also ineffectual because the costs, in both money and individual liberty, are excessive. Partly this is because few politicians or civil servants have any real understanding of the magnitude of the changes wrought by technology.

As the denial-of-service assault the other day on the Home Office's website (the group Anonymous says it was responsible) and the allegations that Gary McKinnon hacked into US military computers have shown, the most advanced security produced by GCHQ and the Pentagon can be circumvented by teenagers with modems in their bedrooms. This does not encourage confidence that Government departments, no matter how benign their intentions, are competent to preserve the security of personal data.

The "reassurance" that records will be of what emails have been sent, and which sites visited, but their contents will not be inspected, is another indication that the powers that be have no conception of how centrally technology has transformed many people's lives. From internet history, and information such as location services on mobile phones, it would, for many individuals, be possible to determine not only where they were, what they bought and to whom they talked, but to account for almost every passing thought they had.

Many of us live now in what used to be called cyberspace; for them, the level of supervision being proposed by the Government is more intrusive than the watch being kept on Abu Qatada. The Tories said all this in as many words two years ago. They were right then, and they're wrong now.