The police protect us, but occasionally we also need to be protected from them

Who will guard us against our guardians, who will secure us against our security services? That age-old question is raised in a vivid way by the incident at Heathrow airport last Sunday.

The police at Heathrow detained David Miranda for nine hours, questioned him in his own words about his "whole life", and raided his computer, his thumb drives and his mobile phone. And they did this, apparently, in full compliance with schedule 7 of the Terrorism Act 2000.

Miranda is no terrorist but happens to be the partner of Glenn Greenwald, the Guardian journalist who published most of the documents leaked by Edward Snowden.

The authorities have made a number of suggestions as to why we ought not to be disturbed by this episode. None of them is persuasive, none reassuring.

One storyline has been that there is no reason for concern because this was normal police procedure, not a politically motivated decision. As a home office spokesperson explained: “It is for the police to decide when it is necessary and proportionate to use these powers.”

The idea mooted here is presumably that we should not be concerned about police conduct when it is taken at the discretion of the officers involved and not under pressure from on high. But that’s hardly a source of consolation. It still conveys the message that each of us passes through Heathrow, or any international transit point in Britain, at peril of being subjected to similar treatment.

Another suggestion has been that we ought not be concerned about Sunday’s episode, since the police did what they did in the cause of fighting crime and terrorism. A statement from London’s Metropolitan Police argued in this vein that “holding and properly using intelligence gained from such stops is a key part of fighting crime, pursuing offenders and protecting the public”.

Protection from police protection
This justification should hardly console us either. As the principle cited at the beginning implies, not only do we need to be protected by the police; we also need to be protected from the police. The experience of Miranda at Heathrow suggests that Britain's legislators ignored this insight in their design of schedule 7 of the Terrorism Act.

If it is possible for the police, at their own judgment, to detain and interrogate someone without any apparent connection to terrorism, then it is possible for the police to treat any one of us in the same way. After all, there appears to have been no ground for detaining Miranda other than the fact he was associated with a journalist who had exposed the United States to adverse publicity. It is ironic, of course, that that publicity related to the sort of invasive abuse exemplified by the police action itself.

A final suggestion as to why we ought not be unduly concerned has been that the police action was an atypical exercise of the police’s power under schedule 7, and not indicative of their general conduct.

David Anderson, the official and independent reviewer of terrorism legislation, may have unwittingly put this in circulation when he told the BBC: “It is such a wide power that it would be surprising if it was used perfectly on every occasion.”

It is consoling when nature causes flood or fire to be told that this is unusual and that we are unlikely to face such hazards often. But it is not equally consoling to be told that a human agency only rarely behaves in a hostile fashion. How an agency behaves displays the power it enjoys and its capacity to exercise that power whenever it chooses. The invasive detention of Miranda may have been unusual but it shows what the Heathrow police are entitled to do, even in dealing with someone in the public eye. It tells us that when we enter the ambit of their control, especially we who lack any public visibility, we are vulnerable to that power and we depend on police grace and favour for even the basic forms of respect.

I do not say that it is unnecessary to give the police some special powers to guard against large-scale dangers to the public, including the dangers so vividly associated with airline travel. But I do say that special powers should only be available for exercise under special precautions and special procedures.

The safeguards needed include tight constraints on when the special powers can be triggered; exact specifications of how they can be exercised; effective channels of complaint for those affected; independent reviews of how the powers are used; and tough sanctions for any officers found to be at fault. Only if such safeguards are firmly and manifestly in place will the special powers of our security services allow us to walk with confidence in the airport concourse or indeed the public square.

Innocent concerns
The issue raised by the Heathrow incident goes to the heart of constitutional concerns. It is because our freedom is at risk that we need security against terrorist threats. But freedom requires security on a general front: a ground for assurance that when we pursue our innocent concerns, we are not exposed to the power of any agent or agency, even a security service, to intrude at will in our affairs. It was not just David Miranda's freedom that suffered in Heathrow. How he was treated shows how anyone can be treated. And the fact we can be treated in that way already demonstrates our freedom is a little less substantive than we might have hoped.

Philip Pettit is an Irish philosopher who teaches at Princeton University. His most recent book is On the People's Terms: A Republican Theory and Model of Democracy (Cambridge 2012)