Peers demand that Goldsmith explain the legal basis for war

The Attorney General, Lord Goldsmith, will be summoned before the House of Lords next week to justify the legal basis for a war on Iraq.

Liberal Democrat peers called the half-day debate after ministers repeatedly refused to explain how a war could be justified without breaching Britain's obligations in international law. But ministers also face the prospect of criticism from the ranks of distinguished former law lords and experts on international law who line the benches of the House of Lords.

Yesterday Charles Kennedy, the Liberal Democrat leader, wrote to Tony Blair asking how a war could be legal if it was not backed by a fresh United Nations Security Council resolution. Ministers have been under pressure over the legality of military action after Kofi Annan, the UN secretary general, warned this week that unilateral action by Britain and the United States "would not be in conformity with the UN charter".

Mr Kennedy wrote: "It is still not clear whether the Attorney General has advised the Government that unilateral military action in Iraq, without a second UN resolution authorising force, would be legal. When I asked you this question earlier today, you chose not to answer it."

Lord Goldsmith joined senior cabinet ministers in Downing Street for a meeting of the "embryonic" war cabinet.

Lord Goodhart, the Liberal Democrat peer, who will open Monday's debate, said: "This is obviously the critical issue of the moment. It is something that we want to bring up. There is a large amount of expertise in the House of Lords. We don't know what the Attorney General has advised." Yesterday senior lawyers warned that military action would be illegal without a second UN resolution. Lord Archer of Sandwell, a former Labour solicitor general, said a war without a second resolution would be "flagrantly unlawful".

Rabinder Singh QC, a human rights specialist, told BBC Radio 4: "The most recent resolution 1441 clearly does not authorise war against Iraq. What that did is to say that Iraq had to comply with certain steps, Blix then had to report back to the Security Council and then the Security Council would decide what to do next."

"The Attorney General has been advising the Government on this. What is noticeable is that there seems to be a one-sided legal debate. At present nobody on the Government side seems to be engaging in a legal debate with us."