This risks strangling freedom without any security gain

Today was a bad one for both liberty and ­democracy in Britain. An unnecessary, illiberal proposal to extend the period of detention without charge to 42 days should never have got this far in the first place. The Brown government should never have pressed it to this vote, mingling the high rhetoric of national security with Tammany Hall vote grubbing. Whatever their motives — in some cases, ­possibly even the right ones — most Labour MPs failed us ­last night. We should not have to ­depend for the defence of our freedom on unelected lords, judges and journalists.

Let us be clear. Our liberties are under threat from two sides. They are threatened by terrorists, especially takfiri jihadist ones, exploiting new technologies and an open society in order to kill, maim and terrify the innocent. And they are endangered by overreaction from the state, eroding those liberties in the name of defending us against these threats. Taken to the extreme, that means strangling freedom to save it.

We have to balance our policies to defend against both dangers. Extending the detention period to 42 days gets that balance disastrously wrong. That's why no other free country with a comparable common law system comes close to it. And, as the Council of Europe's human rights commissioner points out in a warning letter: "This would be way out of line with equivalent detention limits elsewhere in Europe."

Britain's own counter-terrorism leaders are divided. Some are for it, otherwise it would not have come up in the first place. But the overwhelming weight of opinion among those in a position to know is that the government has failed to make its case. The roll call starts with the country's serving director of public prosecutions, Sir Ken Macdonald, who has said in words of one syllable that 28 days is enough. It continues with a former lord chancellor (Falconer), attorney general (Goldsmith), prime minister (Major), lord chief justice (Woolf) and many others, including human rights lawyers who warn the bill has insufficient safeguards and may violate the European convention on human rights. Even those who are for it, like Lord Stevens, the former head of the Metropolitan Police, don't claim that police investigating complex international terrorist plots actually need it now; they say the police probably need it some time soon, so better let the police have this power "in their back pocket". Yet serving senior officers are quoted as saying that it would be counter-productive.

The message we get from ministers is as simple as it is patronising: "Trust us, we know things you don't." Or as the Blair government assured us over Iraq: "Our intelligence tells us …" In regard to 42 days, ministers let it be known that the security services were pressing for this extension. Now a statement from the head of MI5 has, diplomatically yet unambiguously, made it clear that this was not the case. So our rulers have been caught sexing up the dossiers again. "Trust us"? Why should we?

Meanwhile, let's look at the evidence we have so far to understand what 42 days would mean. Anthony Barnett has done some of the detective work in a recent article on opendemocracy.net. He establishes that roughly half of those detained under existing limits (seven days under the 2000 Terrorism Act, 14 days since 2003, 28 days since 2006) were released without charge. Only six suspects were held right up to the 28th day, of whom three were then charged and three released without charge. Pressed by David Davis, the shadow home secretary, the police revealed that those released were not then placed under a control order or even under surveillance. "So they were innocent?" Davis asked. The police responded with what Barnett calls "a shrug of assent".

Consider, for a moment, the human reality behind that "shrug of assent". Here in Britain — not in Pinochet's Chile or Stalin's Russia, but in a land that some of us used to believe was among the freest in the world — a man or woman is picked up on the street, imprisoned and interrogated for four weeks, then released without charge or explanation. "Sorry, mate, off you go." If they even say "sorry". Four weeks. And now, in very exceptional cases, they want to make it six. Some of those released will be bad people who just got away with it this time; but that can't be true of all the 50% who are released without charge.

Suppose this happened to you. ­Suppose you really were innocent. Imagine how you would feel. And the home secretary says this won't contribute to the radicalisation of already deeply disaffected young Muslims. Tell that to the marines. Or rather: tell it to local community police, who know better. In a larger frame, this is presented as a trade-off between security and liberty. Yes, there often is such a trade-off; and, yes, many people put security before ­liberty — 69% of the British public support 42 days "in exceptional circumstances" according to a poll in yesterday's Daily Telegraph, though so much depends on exactly how you ask the question. But such is the likely ­negative impact of this measure on the very people whose ­loyalty to Britain we most need to win, that we might end up being less secure as a result. So, less liberty in return for less security. What an irresistible offer.

This all comes, as the former prime minister John Major pointed out in a quiet Exocet of an ­article, in a larger context in which this country has moved further than most other liberal democracies towards a national security state and surveillance society. Revealingly, in a piece making the case for 42 days, Peter Clarke, a notable former head of Scotland Yard's counter-terrorism ­command, dismisses the ­"alleged panacea" of telephone intercept evidence, testifying that "of the dozens of terrorist investigations that I led over nearly six years, I can only recall a handful where the use of intercept would have made a difference". Yet this is the government that is now allowing almost 800 public bodies to make an average of nearly 1,000 requests a day for intercepts of various kinds (phone, post, email etc). For what good purpose?

And then there is the way in which they rammed this through a reluctant House of Commons, making incoherent "concessions", sacrificing basic principles of sound judicial procedure for political expediency, and offering scrapings from the pork barrel to any Tom, Dick or Mary who might be persuaded to vote for it. This from a prime minister who promised us strategic government based on high principle, and proclaimed the keynote of Britishness to be liberty.

And all for nothing: so hedged about is the 42-day provision by now that it is most unlikely ever to be used except in a real national emergency, in which case something similar could have been done anyway, under existing legislation. Lords, judges and journalists will delay if not prevent its final passage on to the statute book. And if the bill does get there, a Conservative government will almost certainly repeal it. So this has been an exercise in muddled illiberal futility. It almost makes you want to move to Germany.

Timothy Garton Ash