Yesterday The Times reported the case of Lofti Raissi, an Algerian pilot who was being watched by the FBI as a possible suspect in the aftermath of the September 11 attacks. The request to Scotland Yard was to monitor him “discreetly”. Instead, police mounted a dawn raid, put a gun to his head and led him naked to a waiting police car. It turns out he was innocent.

Terrorism, of course, writes its own rules. Police can reasonably argue that when it comes to dealing with desperate men intent on murder, no room can be left to chance, that the only way of ensuring officers’ safety is to go in hard, using shock and awe to subdue resistance. There are, however, two drawbacks. The strategy allows no margin for error, and every time it goes wrong it damages the trust and confidence that are the essential link between police and public.

The unfolding revelations about the death of Jean Charles de Menezes, the young Brazilian shot by mistake after the failed London bombings in July, show what can happen when extreme measures become the first option rather than the last resort.

Operation Kratos (the word means strength in Greek) is the name given to the Metropolitan Police’s “shoot-to-kill” policy. It should, by its very nature, have been the ultimate sanction. The more we hear, however, about the events leading up to the frantic pursuit and grotesque execution of Senhor Menezes, the clearer it becomes that shoot to kill was the priority from the moment he was targeted by his pursuers and allowed to enter the Tube station. Tactics had taken precedence over intelligence.

That ghastly mistake presented Sir Ian Blair, the Commissioner of the Metropolitan Police, with an opportunity to explain the limits within which his officers would operate, and to reassure the public that restraint would play as great a part in the police lexicon as ferocity. Instead he saw his principal task as bolstering the morale of his men. His comment that the police team was “playing out of its socks” was issued before he knew that a mistake had been made, but even so it came across as crude and insensitive. When, 24 hours later, the true facts emerged, he should have qualified it at once, expressing contrition for having made it. At the very least, Operation Kratos should have been withdrawn until the inquiry into Senhor Menezes’s death was completed.

Fighting terrorism will always provide a defence of sorts for extreme tactics. But police overkill goes beyond the business of guarding the nation’s security. Drug raids are now regularly staged with television cameras on hand to record the moment when doors are battered down and suspects led away in handcuffs. We rarely hear how many of those seized are later charged and convicted. Rounding up football hooligans provides an excuse for similar raids. In both cases, the violence is the message — gung-ho behaviour shows the police acting tough and crime being suitably punished.

There is no such excuse for the way in which asylum-seekers are now treated. Last week the Vucaj family from Kosovo, who have been living in Glasgow for the past five years and have been fighting deportation, were arrested and removed to a detention centre near Luton. They were not just removed, they were manhandled. Arrested by immigration officers in a dawn raid, the father and his eldest son were handcuffed, the children taken out of the house in their pyjamas, the mother given no opportunity to collect her possessions.

There is no possible justification for this brand of officially approved brutality. The Vucaj family had been model citizens during their time in Glasgow, the children popular and successful at school. The least they might have expected was a dignified departure. The Home Office, whose slogan proclaims itself as “building a safe, just and tolerant society”, is doing nothing of the sort.

Kathleen Marshall, Scotland's commissioner for children, put it a great deal better. “We usually discuss human rights as lines in the sand,” she said. “That we should cross them just because it becomes expedient . . . I find very distressing.”

The Vucaj case is far from unique. Not long ago I spent a week in Glasgow talking to asylum-seekers, all of them, for the time being, legally present, many of whom will eventually be granted the right to stay. I heard accounts of dawn raids, unexpected detention and an atmosphere of intimidation at the grimly named “enforcement unit”, to which they are required to report every week.

Yesterday Tony Blair addressed the issue of criminal justice. He said that the problem lay with the system itself. In his view, it needed toughening. “It doesn’t mean abandoning human rights,” he added. “ It means deciding whose come first.” He proposed “a radical extension of summary powers to police and local authorities”. No mention here of building trust in the police, of the need for balance, moderation or civilised standards.

Yet these too are the foundations of a safe society, more important by far, and certainly more effective, than the helmets, the visors and the sledgehammers.

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