A leading Labour critic of Gordon Brown's 42-day terror detention plan predicted today that the legislation would have a "very rough ride" in the Lords.

Lord Goldsmith, the former attorney-general under Tony Blair, also accused the Prime Minister of having pushed the measure through the Commons yesterday purely to show his "political virility", echoing a widespread view that it has little chance of making it onto the statute books in its present form.

A revolt by 36 Labour backbenchers left the Government dependent on the votes of Northern Ireland’s Democratic Unionist Party as the proposal scraped through by just nine votes. Both the DUP and Downing Street have rejected Tory charges that some kind of 'dirty deal' was done behind the scenes.

Lord Goldsmith, who has been one of the most high-profile opponents of extending the maximum detention without charge to six weeks, told BBC Radio 4's Today programme: “My fear is that this particular issue over the period of detention without charge has become a symbol of political virility.

"It is too important for that, not just because it concerns national security and our safety, which is hugely important, but also because it concerns fundamental values and the basis of our society, which is also hugely important.

“I have no doubt it’s going to get a very rough ride in the Lords and I, as I have consistently been, will be one of those who will be opposed to this measure. The Government doesn’t have an in-built majority in the Lords, and there will be ... some within the Labour benches who will find this very hard to support.”

Lord Goldsmith added that peers would be bolstered by the wafer-thin nature of the Commons majority into believing they would be right to demand that MPs reconsider.

“People say that we need to have this power because the terrorists threaten to destroy our way of life. Well they do, but I fear that we give it away ourselves if we start to undermine those fundamental freedoms,” he said. "We send a bad message if it looks as though we are prepared to pass repressive laws because we think that one day they might be needed.”

But his view was rejected by Lord Carlile, the Liberal Democrat peer who act as the independent reviewer of the UK’s anti-terror legislation.

“Like almost all senior police officers who are involved at the hard end of this dreadful business of trying to protect the public against terrorism, I believe there are entirely predictable and potentially terrible events that could occur in the future for which we should have law ready now," Lord Carlile said.

“I am very anxious that the law should be set firmly in place so that we do not have to be hysterically reactive to some event in the future. We need to have laws fit for the future.”

Lord Goldsmith also criticised Jacqui Smith, the Home Secretary, for suggesting that he only changed his mind on the issue after leaving government, pointing out that he had also opposed within the Cabinet Mr Blair’s attempt to extend the limit to 90 days. He said that he would have quit office rather than vote for it.

The Conservatives claimed that Mr Brown offered deals worth £1.2 billion to secure the support of wavering Labour backbenchers and DUP MPs whose votes finally won him victory by 315 votes to 306. No 10 insists that no deals were made, but the suspicion nevertheless persisted in Westminster today that Peter Robinson’s party secured some sort of additional support for Ulster.

One DUP MP, Gregory Campbell, said today that no “extraneous” matters were discussed yesterday, although the party hoped for constructive talks in the near future.

“It was on the principle, on the basis of the merits of the case either for or against,” he said. “Those were the issues that the meetings were about, not about extraneous and equally important matters - matters about which we will now have meetings with the Government from now on in.

“We have had constructive meetings about these other issues for months. We will have constructive meetings, I hope, in the future about these issues. That would have happened irrespective of the vote on 42 days.”

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