In 1988 Rajiv Gandhi stood before the UN General Assembly and stated the terrifyingly obvious. Nuclear war would not mean the deaths of 100 million people, he said, or even 1,000 million. It would mark “the end of life as we know it”.

Two decades on the United States and Russia still maintain stockpiles of about 5,000 and 6,000 nuclear warheads respectively. At least 40 countries in all possess nuclear materials, and by some estimates there is enough surplus uranium and plutonium in the former Soviet Union for another 40,000 weapons. For these reasons alone, the appeal by Sir Malcolm Rifkind and the lords Owen, Hurd and Robertson, writing in The Times today (see page 26), for Europe to rededicate itself to nuclear disarmament and non-proliferation, is vitally important for Britain's security.

The authors of the appeal are following that of a similar effort launched last year in the US by Henry Kissinger, George Shultz, William Perry and Sam Nunn. Hoping chiefly to be heard by the next occupant of the White House, they noted that America's reliance on old-fashioned deterrence to deter new types of enemy was “increasingly hazardous and decreasingly effective”. They are right, and the significance for defence planners is immense. Not only is the world's treaty-based non-proliferation apparatus not working; having nuclear weapons is also not working as intended originally either.

Hence the aspiration of the elder statesmen of a world without any nuclear weapons at all. It is a vision borrowed not from CND but from Ronald Reagan and Mikhail Gorbachev, who articulated it in Reykjavik in 1989. In that year communism was collapsing and anything seemed possible. But with the end of the threat of mutually assured destruction that had prevented a Third World War, came a wave of determined nuclear proliferators and the long twilight of the the treaties signed by the Cold War superpowers to keep armaggedon at bay.

The Anti-Ballistic Missile Treaty was torn up by the US in 2001. The Nuclear Non-Proliferation Treaty has proved powerless in the face of nuclear nationalism in South Asia and Iran. The Comprehensive Test Ban Treaty (CTBT) was passed in 1967 but remains unratified by nine key states. And the latest START disarmament pact, signed in 1991, expires next year.

Seventeen years into the post-Cold War era, the world has no post-Cold War nuclear treaties. It needs some urgently, and the basis must be a new accord between Russia and the US, which between them still hold 95 per cent of the world's nuclear weapons. Russia must recognise missile defence as a sane response to the growing Iranian threat. The US must ratify the CTBT. Both powers must continue dismantling their own arsenals under a successor to START, and they must take the lead in strengthening the International Atomic Energy Authority as a global enforcer of non-proliferation.

Acquiring nuclear weapons is the dream of rogue states and international terrorists, and preventing that dream becoming the rest of the world's nightmare is the most compelling reason since the Cold War for meaningful international co-operation. A world without nuclear weapons is an unrealistic goal in 2008, if ever. But an nuclear summit early in 2009 between presidents Medvedev and Obama or McCain is not.