The hardest part in dealing with emergencies amid highly charged political debate is not to overreact. Gordon Brown well knows the scale of the threat that terrorism poses to Britain: within his first week in office, three failed car bombs came close to killing hundreds of people. Since 2001, the Prime Minister told the House of Commons yesterday, there have been 15 attempted attacks. Police and security officials are currently contending with 20 known plots, monitoring 20 groups and have about 2,000 individuals under scrutiny. The measures announced yesterday will not make that surveillance any less necessary. But they do address the gaps and flaws in legislation and practice that terrorists have exploited and that have made Britain too easy a target. It is uncomfrotable to admit that the country faces a threat, but to ignore that reality would be to abrogate political responsibility.

The most eye-catching idea is the creation of a dedicated border force, bringing together immigration and customs officers with powers to detain those suspected of immigration offences. The details have yet to be worked out. But much can be learnt from the experience of other countries, and the Prime Minister deserves credit for setting aside political prejudice and accepting an idea put forward by the Conservatives. The introduction of biometric visas will make the new force’s task easier, as will the setting-up of electronic exit controls at UK borders from 2009 so that passports can be checked immediately against a warnings index. And linking a UK watchlist of suspects to the Interpol database of lost and stolen documents is plain common sense. Why is this not already in force?

Preventing terrorists entering the country is one issue; monitoring and dealing with those already here is more difficult. Mr Brown spoke of a “growing weight of opinion” on the need to extend the 28-day period of detention without charge for terrorist suspects. He clearly inclines towards the view, robustly championed by the previous Home Secretary, that this should be doubled. But he should think again. There is no proven need for a blanket extension. There may, however, be difficulties in some cases in amassing evidence, especially from overseas or from electronic encryption, within the time limit. The police, therefore, should be given flexibility so that, when genuinely necessary, they could apply to a High Court judge for an extension. Suggestions yesterday that cases should be referred to Parliament are absurd: the most important thing is that the process be sustainable, fair and not open to political interference. Only a judge has the authority to ensure that a police application is not an excuse for incompetence or prejudice.

Equally, Mr Brown should reject suggestions that suspects could be further questioned after being charged. This raises serious doubts about the fairness of trial procedure. It would be far better for police to take longer to make their case, if necessary, and then bring a charge. But the need to admit in court evidence obtained by telephone intercepts is obvious, as long as it does not compromise a source or a technological technique.

‘Items sent as earthquake aid’

Hidden among clothing were goods selected and purchased to support the activities of terrorists, a court was told

Multimedia

• Pictures: Glasgow airport attack

BACKGROUND

• Brown plans to double 28-day detention limit

• Men in bungled raid say police attacked again

• More than Vigilance

• 'Dirty bomb' mastermind plotted wave of atrocities across Britain

• Jihadi house parties of hate

Other issues raised yesterday, such as ID cards, have implications that go far beyond the fight against terrorism. But funds to train English-speaking imams and to help UK madrassas with citizenship education are vital if the vulnerable are not to be left at the mercy of the extreme. Thoughtful change in legal process will ensure that cherished social values will endure.