Dr Hans Blix, the former UN weapons inspector, will launch a new attack on Tony Blair today, warning that the decision to press ahead with a full replacement for Trident will make it more difficult to stop Iran acquiring the bomb.
The respected chairman of the Commission on Weapons of Mass Destruction will use a speech in London to renew hostilities with Mr Blair. He will say that modernising Britain's arsenal puts the non-proliferation treaty (NPT) under "strain" and increases the feeling among non-nuclear states, such as Iran, that they are being "cheated" by the nuclear states.
Dr Blix will take Britain and the other permanent members of the UN Security Council - America, China, Russia and France - to task for failing to comply with their obligations under the NPT by failing to do more to eliminate their nuclear arsenals. He will point out "the strong feelings of frustration" at the way nuclear nations "are in the process" of developing new types of weapons rather than examining how they could manage defence needs with non-nuclear weaponry.
His remarks, in a speech to the British Institute of International and Comparative Law, follow the decision of the Cabinet last Thursday to "whip" a decision on the replacement for Trident through the Commons in the new year. Although the Tories are likely to back Mr Blair, there is strong concern over the issue on the Labour back benches.
Dr Blix will tell the international gathering of lawyers that his Stockholm-based WMD Commission believes the UN General Assembly should call a world summit on disarmament to revive the NPT efforts to reduce the risk of a nuclear war.
He will say it is 60 years since the UN called for the elimination of all nuclear weapons, but there has been a fragmented approach to tackling nuclear proliferation. The five members of the nuclear club have been joined in recent years by Israel, Pakistan, India and North Korea.
The Commission, Dr Blix will say, believes top priority should be given to ratification of a comprehensive nuclear test ban treaty, including North Korea, the latest member of the "nuclear club".
Dr Blix infuriated Britain and the US before the Iraq war when, as the leader of the inspection team on WMD, he challenging the "dodgy" dossier claiming that Saddam Hussein possessed chemical, biological or nuclear weapons. Rebel Labour MPs said last night he had been proved right over Saddam's WMD, and they believed he would be proved right again over Trident.
MPs have been demanding a wide debate on the options. Some senior MPs, reported to include Geoff Hoon, the former defence secretary, have questioned the wisdom of backing the most expensive option favoured by the chiefs of staff, instead of a cheaper alternative such as nuclear-tipped cruise missiles on planes.
However, a White Paper setting out the Government's preferred option will be published next month and Labour MPs will be told to back it. They will be allowed three months for "debate" but Labour MPs will be "whipped" to support the cabinet decision in a vote in the Commons in the new year.
Peter Hain, the Northern Ireland Secretary, and a former member of CND, defended the decision to push the issue through Parliament on a whipped vote. "You couldn't expect a serious government in charge of one of the world's global powers, Britain, making a recommendation to Parliament and just say you can do what you like chaps ... and make your own mind up," he said on the BBC AM programme. "We're a serious government and serious Cabinet. We will put our view when that view is finalised by the Cabinet, and it hasn't been yet. We've not had a further cabinet discussion on the detail of all of this. We'll make a recommendation through a White Paper. Then there'll be a full debate."
Gordon Brown, the Chancellor, has already made it clear he will support the most expensive replacement for Trident - a new generation of submarines, with US-designed missiles and a new nuclear warhead. Early estimates suggested it could cost £25bn, but some experts have claimed the true cost could be nearer £76bn over 30 years.
Mr Brown's position on the issue has dismayed even some of his own supporters. Other Labour MPs rallied behind Dr Blix. Neil Gerrard, a Labour MP who tabled a Commons motion signed by more than 20 Labour colleagues warning the Trident replacement would breach the terms of the NPT, said Dr Blix would strengthen opposition.
"Dr Blix was proved right on WMD and a lot of people will agree with what he is saying now," he said. "It is possible that Mr Blair will lose a majority of Labour MPs on this issue."
The ending of the Cold War has changed the argument in the Labour Party. It is no longer a simple divide between those favouring multilateral disarmament and those supporting unilateral disarmament. Dr Blix's speech will increase the doubts among those who question the value of a more powerful nuclear weapon with multiple warheads designed to penetrate "hardened" targets, when the foreseeable threat is from rogue states or terrorists. Unlike in the 1980s, there are significant military figures with doubts over the renewal of Trident.
A spokesman for Greenpeace, said: "Hans Blix said that invading Iraq to tackle concerns about WMD was wrong. He was proved correct. Now he's pointing out that the Labour Government building new WMD "because of an unknown future" is wrong and will destroy the UN disarmament process. Let's hope this time Labour listen."
The other nuclear states
* US: 10,000 warheads, Trident fleet being extended to 2,040 but developing "mini-nukes" for tactical battlefield use
* FRANCE: 482 warheads on air-to-surface missiles and ballistic missiles on subs being modernised
* RUSSIA: Ageing arsenal of 15,000 warheads which it is seeking to put into storage
* CHINA: Unknown, but thought to have 100 to 500 nukes, mostly ageing, keen to avoid race with US
* ISRAEL: 200 warheads, getting nuclear-capable subs from Germany
* INDIA: 150 warheads, has not tested since 1998 but recently tested missiles.
* PAKISTAN: 50 warheads. Not tested since 1990s, but tested missiles recently.
* NORTH KOREA: Tested first nuclear bomb this year
South Africa, Ukraine, Kazakhstan and Belarus have all disarmedReuse content