The two most senior legal figures in Tony Blair's cabinet will today lead a devastating assault against plans to hold terror suspects without charge for up to 42 days.
Lord Goldsmith, the former attorney general, made it clear yesterday that he was prepared to defy the Government and vote down the measure. Lord Falconer, the former Lord Chancellor, is also expected to attack the plans in the Lords when peers open debate on the Counter-Terrorism Bill this afternoon.
Lord Goldsmith insisted the measure was "wrong in practice and wrong in principle".
The two men, who occupied pivotal positions in Mr Blair's government after the terror attacks on London and in the run-up to the invasion of Iraq, are among nearly 50 peers due to speak during today's debate amid growing anger at the plans, which only scraped through the Commons last month by the nine votes of the Democratic Unionist Party. The intervention of two such senior Labour figures will pile pressure on Gordon Brown, who already faces months of pitched parliamentary battles over the Bill.
Mr Brown faces a drubbing in the Lords when peers vote on the Bill later this year, with critics predicting that plans to extend the current 28-day limit on holding terror suspects without charge could be defeated by more than 200 votes. Sources have predicted that a string of Labour rebels would join Conservative, Liberal Democrat and cross-bench peers to throw out the measure, heralding a fresh round of parliamentary trench warfare for the Government when the legislation returns to the Commons.
A spokesman for Lord Goldsmith, whose legal opinion on the legality of war was crucial in the run-up to the invasion of Iraq, made his opposition to the anti-terror legislation clear. He said: "He is prepared for people to know he will vote against the Government at committee stage. He thinks it will be counter-productive and all his experience when he was attorney general looking at these cases in real time shows this is not needed."
By tradition, peers will not vote on the Bill after today's second reading debate. But peers say the 42-day plans will be overwhelmingly defeated when the Bill reaches its detailed stages after the Parliamentary break.
Yesterday both Conservatives and Liberal Democrats said that they stood firm against the measure. Lord Thomas of Gresford, who will speak for the Liberal Democrats, said: "On the eve of the vote our position remains as hard as it always has been. We cannot be bribed by knighthoods, peerages or larger rooms. On the Labour benches there is significant opposition. On the cross benches there will also be some very powerful speeches made against it by people with genuine experience of terrorist cases."
Dame Pauline Neville-Jones, the former Joint Intelligence Committee chairman and the Conservative spokesman for homeland security, added: "The Conservative Party strongly supports effective action to disrupt terrorists and bring them to justice and is very critical of the Government's feeble efforts to enforce its own legislation outlawing support for terrorism.
"But it will continue to oppose the Government's obnoxious proposal to extend maximum pre-charge detention from 28 to 42 days when it comes to the Lords on 8 July and where it risks heavy defeat. The Government has utterly failed to demonstrate the need for this further extension of police power and, as the former home secretary Charles Clarke has pointed out, the Government's ostensible safeguards against possible abuse are almost certainly unworkable and therefore worthless."