Conference, it is  5 years since we last debated the issue of the nuclear deterrent, when we  adopted our defence policy paper, "Defending Democracy". We agreed then that retention of the nuclear deterrent until we could negotiate nuclear weapons away through multilateral negotiations was the prudent course against an uncertain future. We spelled this out in our 2005 general election manifesto. Since then, the world has not become a safer place. North Korea has joined the other 8 nuclear powers. Iran has been less than honest in its nuclear enrichment programme. China has tested an anti-satellite weapon. Russia has threatened to start building intermediate nuclear range missiles again against Poland and the Czech Republic in response to US missile defence plans. And on the multilateral disarmament front, the prospects have also become bleaker with the failure of the non-proliferation treaty review conference in 2005. None of this means that we are necessarily returning to the days of the Cold War, but we cannot argue that recent developments are encouraging. We need to get disarmament moving again.

In that light, we are considering this morning  whether an immediate change to our policy is necessary. The catalyst for this debate has been the Government's rush to make a decision about the next generation of the nuclear deterrent. While they looked at a number of options for new systems, they have recommended nothing new for the nuclear system. The Trident missiles will continue through a life extension programme until 2042. The nuclear warheads will remain the same. Only the four submarines are to be replaced. As our background paper explains, the government has spun a false sense of urgency over this need for new submarines. They have knocked five years off the planned life of the current submarines, added 3 years to the normal procurement time, and declared that submarine life extension is not possible. All this is at the behest of the defence industries, who claim that they must build a new submarine every 22 months to maintain their expertise. So we are, not for the first time, being rushed into an unnecessary decision because the defence industries demand it. 

The FPC motion today outlines how the decision can be deferred safely until at least 2014. Reducing to 3 submarines gives an extra 2 years before replacement would be necessary. As the lead letter in the Guardian yesterday, signed by leading NGOs, showed this is the approach that has widespread support. Last month The Independent featured 100 opinion formers following our line.

The extra time is important, not just to look for cost effective solutions, it is vital to try to get the arms control process up and running again. The next NPT review is in 2010. It is in all the world's interest to get back to negotiating down the number of nuclear weapons. We, the UK, have a very special position in such negotiations. We are one of the five nuclear powers recognised by the Non Proliferation Treaty. This means that we are a key player for influencing progress on global disarmament. Given the terrible state of arms control, the time is right to be dramatic in what we offer. The FPC motion calls for an immediate cut of 50% in our warheads to kickstart arms control negotiations. This would demonstrate our seriousness about global nuclear disarmament; but it would still be sufficient to provide credible deterence in the interim. Strangely, Amendment 2 seeks neither route. It would maintain the current nuclear system for 20 years or so, and ignore the disarmament opportunities.

Just as with Iraq, Tony Blair is again rushing in to commit us to a course action before all the options have been explored. Sadly both of the main amendments to the motion fall into the same trap. The first amendment seeks to commit us to a real new generation of nuclear weapons with the French. Not only will this be both costly and by no means certain of success, work would need to start very soon. We would have committed ourselves to developing with the French a new generation of nuclear warheads, missiles and submarines, at a time when our armed forces have so many other calls on the defence budget. The second amendment would mean that we declare now that we will keep the current system, but not  replace it. We thus  close off our subsequent influence on multilateral disarmament, or perhaps we find ourselves in a new Cold War less protected than in the last one. We would  also pay the costs for a system that we have made incredible by our announcement.

 Nuclear strategy is a cause for great passion. Deterrence only works because the consequences of its failure are so terrible. That gives rise to deep and difficult ethical questions. A nuclear weapon has only one purpose: to prevent the use of other nuclear weapons. The nuclear taboo on use has existed for the last 61 years since Hiroshima and Nagaski. We must drive down the global nuclear stockpile until there are no more, however long that takes. Doing this safely means maintaining deterrence, while nuclear threats are unconstrained. But it also means seizing the moment to reduce when we can.

The FPC Motion offers a continuation of Lib Dem policy but with a dramatic downsizing of our nuclear arsenal, yet not putting our security at risk. We will not be rushed into precipitate decisons by the defence industry or a departing Tony Blair. We must use the next decade to get arms control moving again so that we do not need a successor to Trident when the time comes to make the key decision. I urge you to support the motion and oppose both of the amendments.

(Motion was agreed to and amendmendments were defeated)