Now, all that has changed utterly. The Government seems ready to exploit the national fear by riding roughshod over principles which have long been sacrosanct. In a fearful society, it is easy to persuade people that the old rules no longer exist. Easy, and dangerous.
The Government presents the latest proposal to deport people with supposed guarantees that they will not be tortured as though it were a new idea, devised as an emergency response to the bombings. In reality, it is a mendacious old idea. A year ago the Human Rights Watch report Empty Promises demonstrated clearly and in detail that diplomatic assurances are no guarantee against torture. Four months ago, a 90-page report, Still at Risk, confirmed the point, with yet more evidence. Human Rights Watch and Liberty wrote to the Prime Minister, pressing the point. The Government, however, seems uninterested in facts. It proudly announced this week that it has struck a deal with Jordan on sending people back; it wants to strike more such deals with a clutch of torturing governments in the region.
The evidence shows clearly how flawed such agreements can be. Sweden sent two men back to Egypt in 2001, after receiving assurances that they would not be tortured. They were, of course, tortured. Bizarrely, the United States even claimed to believe Syria (a paid-up member, after all, of George Bush's "axis of evil") when Washington received what it called "appropriate assurances" that Damascus would not torture Maher Arar, a Canadian-Syrian handed over in 2002. (Arar, too, was tortured.)
The phrase "assurances" was not always so polluted. Assurances are given in cases where a suspect is extradited for trial to a country with the death penalty, such as the United States. On such occasions, America assures the delivering country that the (otherwise legal) death penalty will be suspended. Such assurances are within the framework of the law and wholly verifiable. In short, they work.
But the new style of "diplomatic assurances" is very different. Torturers do not like to tell the truth. Governments which practise torture routinely assure the world that they do not do so. What, then, is the point of yet another assurance? If a government regularly breaches international treaties against torture which carry criminal penalties, why should they respect a bilateral agreement which neither government has any real interest in enforcing?
The idea that occasional prison visits will reveal the truth is equally far removed from experience - a person being visited occasionally cannot speak the truth for fear of being sent right back to be tortured.
There are two possible interpretations of what has happened. Either the Government does not understand the significance of all the broken promises that have gone before. Or, on the contrary, it understands all too well - and calculates that, in the current climate, many in Britain will be unbothered about unsavoury characters being sent back to face torture. Some judges might be unhappy, admittedly - but, as the Lord Chancellor and others have made clear in recent days, who cares about judges anyway?
Certainly, it could be easy to persuade those who fear being blown up on their way to work that rules no longer quite matter - just as we saw that the US administration played on American fears, with a lawless Guantanamo, after 9/11. Guantanamo was (presumably) supposed to make the world safer. In the UK, some had hoped for a more intelligent approach. It is depressing if our political leaders fail to understand the importance of the rule of law. Sending people back to the torture chambers is in breach of Article 3 of the European Convention on Human Rights. Nor is this just a European issue. Such deportations are also in obvious breach of the UN Convention against Torture - whose enforcement the UK once worked so hard to ensure. Changing national laws will not make the UK less in breach of international law.
Despite what the Prime Minister says, the rules of the game have not changed - or they should not have done, unless politicians (cynical, foolish, or both) decide that they wish unilaterally to change the rules. Those who have committed crimes, or plotted serious crimes, can be prosecuted. Those whose activities give cause for concern can be placed under surveillance - as happened many times in Northern Ireland. But if the rules of the game now read "Torture is always bad - except as part of the war on terror, when we no longer care", then that is a betrayal of all the values that this country once stood for. If the Government refuses to acknowledge that basic point, we will all be the losers.
The writer is UK director of Human Rights WatchReuse content