Woolf vows he will hold ministers to account when he sits as judge in Lords

The Lord Chief Justice has said that he plans to sit as a judge in the House of Lords where he will hear cases in the country's most important court.

His decision will alarm ministers, who are expecting to have to defend their controversial anti-terror measures in a legal challenge brought to the House of Lords later this year.

In his first interview since announcing his retirement as the country's most senior judge earlier this year, Lord Woolf, 73, says that he is intending to take his place in the House of Lords, where he can be called upon to serve as one of the law lords.

He also says he will exercise his right to take part in debates in the upper chamber, where his presence will be a focal point for any opposition to the Government's anti-terror and criminal justice reforms.

By the time Lord Woolf retires, lawyers for some of the foreign terror suspects, who were arrested and returned to prison this month, are expected to mount a legal challenge to the men's detention.

In December last year the law lords ruled against the Government on indefinite detention without trial, prompting the Home Secretary, Charles Clarke, to recast his anti-terror plans.

The possibility of Lord Woolf joining a panel of judges to rule on the lawfulness of these new measures will worry Mr Clarke and the Prime Minister.

Tony Blair has tried to warn off judges by telling them that the "rules have changed" since the London bombings and that the Government will not tolerate what Mr Blair considers to be judicial interference.

But speaking in Young Bar Magazine this week, Lord Woolf, a defender of the judiciary's independence, says that he has always spoken out if he believes that ministers are threatening the rule of law.

Recalling his ruling last year against the Government's attempts to restrict asylum-seekers' access to the courts, Lord Woolf says: "The decision caused me intense concern because it was an indication that the Government of the day was prepared to tolerate a denial of the rule of law and it was made knowing it would give rise to the danger of constitutional conflict between the government and the judiciary."

Conflict now seems inevitable. The Government has promised to introduce a law that reminds judges hearing certain terror cases that they have a duty to balance any threat to national security against the risk of a foreign terror suspect facing torture if he is forcibly returned home.