The law lords have begun hearing an appeal from nine terror suspects against their detention without trial under controversial government legislation.

The House of Lords judicial committee is sitting in a panel of nine, the maximum possible number, to consider the lawfulness of the indefinite internment powers contained in the Anti-Terrorism Crime and Security Act 2001.

The case is an appeal from an October 2002 decision by the Court of Appeal which ruled that indefinite detention is compatible with UK and international law.

The law lords may also decide to consider the issue of whether evidence from third countries obtained under torture may be used in such cases.

That issue arises from a separate Court of Appeal majority ruling in August 2004 approving the use of evidence obtained under torture as long as the UK neither "procured nor connived at" the torture.

The 2001 Act was a response to the September 11 attacks on New York and Washington, rushed through parliament by home secretary David Blunkett.

Ministers have indicated a willingness to reform the law by allowing security services' bugging transcripts to be used in court, reducing the need for internment without trial, although the legal challenge is understood to have delayed plans for amendments to be included in November's Queen's speech.

But the government is vigorously defending the principles of the legislation, with attorney general Lord Goldsmith leading the defence of the rules in Britain's highest court.