Five men suspected by Britain of "facilitating terrorism" won a High Court battle yesterday against the freezing of their assets, in the latest blow to the government's security laws.

The five, who deny involvement in terrorism, had challenged financial sanctions imposed on them under two laws enacted by the government as "orders in council", a form of legislation which does not require parliament's approval.

"I take the view that both the... orders as they stand are not lawful", High Court judge Andrew Collins said.

The ruling means the government may have to present a new bill to parliament to create a legal basis for freezing the British assets of suspected militants, including alleged al Qaeda and Taliban associates blacklisted by the UN.

Such a bill could be hard to push through, because the stringent sanctions are not subject to review by any court and the government does not have to tell people on what grounds it suspects them of involvement in terrorism.

Prime Minister Gordon Brown was forced into a humbling climbdown on Wednesday over taxation of low earners. He also faces a threatened parliamentary revolt over plans to increase from 28 to 42 days the period for which arrested terrorist suspects can be held in custody before police have to charge them or let them go.

The five men in yesterday's case, named in court only as A, G, K, M and Q, received identical letters informing them of the financial sanctions against them.

"The Treasury has reasonable grounds to suspect that you are, or may be, a person who facilitates the commission of acts of terrorism.

In the light of the sensitive nature of the information on which this decision was taken, we are unable to give you further details," the letters stated.

Under the sanctions, the men or their spouses require a licence from the Treasury to obtain welfare payments to cover essential items like food, and they have to submit exhaustive accounts showing how the money is spent.