Today's ruling by the law lords, which effectively gives legal clearance to the Government’s controversial control order regime, was greeted with relief within the Home Office.

Ministers and officials had been anxious that the ruling would sink a system introduced as a "second best option" when the law lords ruled illegal the indefinite detention of foreign terrorist suspects.

The orders, introduced in 2005, give ministers the power to put individuals who are suspected of involvement in terrorist activity under close supervision, which opponents have argued amounts to a form of house arrest.

Today’s ruling makes clear that the most draconian power - an 18-hour curfew order - breaches the human right to liberty.

But they held that a 12-hour curfew is acceptable, and Home Office officials believe that 16 hours may also be acceptable.

Ministers will continue to use the orders, though the Home Office’s suggestion that a 16-hour curfew may be possible could lead to further court battles over what duration of home curfew amounts to a deprivation of liberty.

Despite today’s ruling, ministers still face a dilemma over dealing with foreign terrorist suspects against whom there is insufficient evidence, or evidence unlikely to be admissable in a criminal prosecution, and who they cannot deport.

Control orders will remain part of a range of government measures for dealing with terrorist suspects but there are indications emerging within Whitehall and the police of other tactics to deal with the problem.

Ministers are looking at making links with terrorist activity an aggravating factor in sentencing for non-terrorist crimes. This would enable the courts to impose longer sentences for credit frauds or possessing false documents when there is evidence that the offences are linked to terrorism.

The use of evidence from telephone intercepts is again being studied by a group of senior Privy Counsellors. Any move to allow evidence from intercepts to be admissable in courts could help to bring prosecutions against some suspects.

But senior police officers and senior government ministers involved in counter-terrorist policy remain strongly opposed to allowing intercept evidence to be used in courts.

Ministers will also continue to seek agreements with a number of states - particularly in North Africa - that terrorist suspects deported will not be subjected to torture or inhumane treatment on their return.

Until any of these measures are implemented, the control order regime will continue to be used - though probably more sparingly than in the past.

Times Recommends

• He stole my son, now I’m alone in hell
• Back on the air, but don’t mention Mugabe
• Ten kitchen gadget gift ideas