The judge said they posed a threat to UK security, but the law says they cannot be deported – a tough test for new Home Secretary, Theresa May, on week one in the job. Two Pakistani nationals were amongst twelve arrested in a counter-terrorism operation in Manchester. In the absence of sufficient evidence to prosecute, eight agreed to return to Pakistan. But, on Tuesday, two others - Abid Naseer and Ahmad Faraz Khan - won a legal battle to stay in Britain for fear of being tortured by Pakistani intelligence, if returned home.

The case has lit up the controversy surrounding the Human Rights Act (HRA), running straight across a fault line in the coalition government – Conservatives want to repeal the HRA, Lib Dems to preserve it. I have long criticised the HRA, and it certainly has promoted unnecessary restrictions on deportation – beyond anything required by the European Convention on Human Rights (ECHR), or the Strasbourg Court. However, in this case, even a Bill of Rights could only marginally improve the situation. The truth is that our membership of the ECHR requires us to respect an absolute prohibition on torture. As difficult as that may be in cases like that, it is a moral standard I believe Britain should maintain. So what can we do?

First, get some perspective. The terrorist threat level is high, but since 9/11 the major threat has shifted from foreign nationals to home-grown terrorists. Control orders were introduced in 2005 to deal with foreign nationals we cannot deport. Their use has declined – at February of this year there were only 14 – and most control orders are now used for British citizens, not foreign nationals. That suggests that our inability to deport suspects back to unsavoury regimes is not the major focus it once was. Still, no cause for complacency.

Second, control orders – which allow virtual house arrest, and other intrusive restrictions – are a clumsy and ineffective way of dealing with individuals who have not been convicted of any criminal offence. They should be phased out. But not until we have a better system in place.

Third, prevention will always be better than cure. And here, we are way behind. UK borders are porous, and Naseer and Khan effortlessly abused the student system by subscribing to a bogus college. Until we set up a dedicated Border Police force, and crack down on the abuse of student visas, we are inviting trouble.

Fourth, where prevention fails – and it can never be full proof – we need our prosecutors to take a zero-tolerance approach to terror. Based on my experience of international war crimes prosecutions, and a visit to the US in 2007 to learn from their counter-terrorism strategy, I am convinced Britain needs a wholesale change of culture. We should not be cosseting extremists who cross the line between legitimate free speech and violence. When militants in London protested against the Danish cartoons (depicting the Prophet Mohammed), by holding placards calling for people to bomb Denmark and the USA, they should have been arrested and prosecuted without delay for inciting murder. What message does it send to law-abiding Muslims – or anyone else for that matter - when such actions are tolerated? So too, where we cannot deport a terrorist suspect, we must try harder to prosecute them within the law, rather than resorting to draconian measures. That means lifting the ban on using intercept evidence in court – Britain is virtually alone in prohibiting such key evidence – and a more assertive use of plea-bargaining, under judicial supervision, to encourage the minnows in a terrorist group to testify against the bigger fish. This strategic approach has worked in the pursuit of international war criminals, and the Americans have deployed these techniques to crack organised crime and prosecute terrorists. That is the way Britain can fight terror, and defend our freedoms.