I am grateful to my hon. Friend for that intervention. I agree. There is real concern—certainly among Labour Members—about the September decision. I do not quite see why it has to be made in September and I would like to think that there could be some movement on this point. We know that the Trident replacement bid is a big issue that will not go away—far from it, as it seems to be getting more and more prominent for a range of reasons. My view, like that of my hon. Friend, I think, is that Trident should have been cancelled many years ago. However, I agree with his point.

Having endured those bleak years, are we now on the way up? There are, in my view, real grounds for optimism. The first is the new Administration in the United States. My hon. Friend Bill Rammell, then Minister of State at the Foreign and Commonwealth Office, told the Foreign Affairs Committee:

"The prospects for disarmament under President Obama are much greater and stronger than they were under President Bush."

That, I think, is incontrovertible.

The new President has declared that he wants to work towards a world without nuclear weapons, to pursue the US ratification of the vital comprehensive test ban treaty and to support a verified fissile material cut-off treaty. As the House will be aware, the US and Russia made progress earlier this week on a joint understanding for a new strategic arms reduction treaty. The START follow-on treaty would reduce the number of deployed strategic warheads and delivery vehicles. Surely that encouraging development points up the difference in President Obama's approach from that of his predecessor. I would go so far as to say that President Obama provides us with the best hope we have had for years in the area of non-proliferation.

Our own Government have shown that they are seized of the importance of progress at next year's NPT review conference. In March, the Prime Minister announced that the UK is to work with other countries to set out a "Road to 2010" plan. I understand that publication is likely to come before the House rises, and I hope that is right.

There are signs of movement at an international level, too. In May the preparatory committee agreed by consensus an agenda for the 2010 NPT review conference. That might not sound like much, but it is a lot better than what has been achieved in the past. Indeed, it was the first time that that has been achieved in the preparatory committee for 15 years. Later in May, the UN conference on disarmament, which had been deadlocked for 12 years, agreed a programme of work, including the negotiation of a fissile material cut-off treaty.

It seems there is indeed scope for progress, and it is vital that we seize this opportunity, because the challenges that we face are urgent. Iran and North Korea are NPT signatories and they have breached their NPT obligations—North Korea has tested nuclear devices. India, Israel and Pakistan have all acquired nuclear weapons since the treaty came into force, with major implications for security in their regions. All three refuse to join the NPT. The NPT nuclear weapons states still hold massive nuclear arsenals, and would continue to do so even after the planned START follow-on treaty is fully implemented.

The security of nuclear material is a great concern, especially as the use of civil nuclear power worldwide is expected to expand. The A.Q. Khan proliferation network shows the ongoing threat of the illicit transfer of technology and materials, and the threat of terrorist efforts to acquire nuclear weapons and materials is surely a continual concern.

So how do we proceed? Looking to the 2010 review conference and beyond, a consensus has been emerging over some of the steps that need to be taken. First, we must see the early entry into force of the comprehensive test ban treaty. It can come into force only when all five nuclear weapons states and all states with civil nuclear reactors have signed. Nine such states, including the United States and China, have still to make this commitment. As I have mentioned, President Obama has pledged to pursue this, and the fact that the Senate is Democrat-led gives further ground for hope.

Secondly, to strengthen measures that prevent the illegal diversion of material to nuclear weapons programmes, we must have universal adoption of the International Atomic Energy Agency's additional protocol, which allows inspectors more intrusive access. The Government recognise that progress here is a priority.

Thirdly, a fissile material cut-off treaty would halt the further production of plutonium and weapons-grade uranium. The Government have identified that as an essential step towards a world without nuclear weapons and, as I have mentioned, President Obama has reversed the position of the previous Administration and reinstated US support for the treaty.

Fourthly, moves to guarantee supplies of fuel for peaceful nuclear energy uses, enabling countries to forgo the development of fuel-cycle facilities, would limit the risk of diversion and of terrorist intervention. If progress is to be made here, participating states must have absolute confidence that supplies would be guaranteed.

Fifthly, we need proper enforcement measures for states that breach or withdraw from the NPT system—a point made by President Obama in his speech earlier this year in Prague. I am pleased to say that this is also a priority of the UK Government.

Sixthly, we nuclear weapons states must take steps to de-alert our existing arsenals, reduce our dependence on those arsenals in our defence policies, and improve our levels of transparency. As UN Secretary-General Ban Ki-moon has pointed out, the fact that we do not even have an authoritative estimate of the total number of nuclear weapons attests to the need for greater transparency.

Finally, we nuclear weapons states have an obligation to disarm. As I have said, disarmament is one of the three pillars of the NPT, and the world is watching closely. The progress towards a successor to START made by the US and Russia this week is an encouraging step in the right direction. Non-nuclear weapons states will need to see that we nuclear weapons states have an ongoing commitment to further, deeper cuts in our arsenals.

This week, Robert McNamara, US Defence Secretary during the Cuban missile crisis, died. Unlike most hon. Members, I can remember the Cuban missile crisis. I was a student and can remember the genuine fear that we all—students and university lecturers—felt at the time. Forty years after that crisis, McNamara famously revealed how close the world came to nuclear war. He said:

"It was luck that prevented nuclear war...Rational individuals came that close to total destruction of their societies. And that danger exists today."

The case for a world without nuclear weapons was made by Robert McNamara in one sentence, and I will close with it today. He said:

"The major lesson of the Cuban missile crisis is this: the indefinite combination of human fallibility and nuclear weapons will destroy nations."

Surely the greatest security challenge facing us today is to do all that we can to ensure that that does not happen—not in our lifetimes, not in our children's lifetimes, not in our children's children's lifetimes: not as long as mankind inhabits this planet.