Indeed, it remained largely science-fiction. When the Soviet Union collapsed, the technology had failed to get far from the drawing board. By the end of the Cold War, Russia and the US maintained an agreement not to deploy anti-missile systems.

Twenty-five years later, the Cold War may be over, but the "Son of Star Wars" is casting a long shadow over the North Yorkshire moors.

Of the threats Britain faces today, a superpower nuclear conflict is, thankfully, one of the least likely. Yet though the prospect of all-out war is remote, the US and Russia still retain thousands of nuclear weapons.

Nuclear proliferation to other states remains a pressing concern. While there are so many nuclear weapons in the world, there is always a danger that by accident, by terrorist intent or by regional confrontation, something may go badly wrong. The cost of such an event would be incalculable.

Ironically, the world's nuclear powers seemed to make more progress on nuclear disarmament at the height of the Cold War than they have done in times of peace. The Bush White House has made precious little attempt to reduce arsenals or tackle proliferation by multinational negotiation.

Instead of leading the charge for new international arms control agreements, George W Bush has resurrected a "Son of Star Wars" in the form of the Ballistic Missile Defence system.

This time it is intended as a means to defend against nuclear attack from so-called "rogue states". Complicit with Bush's plan, Tony Blair and now Gordon Brown have consented to the use of US bases at Fylingdales and Menwith Hill as critical components of the system.

Yet there has barely been any public debate about the venture. The establishment Labour-Tory consensual view in Westminster is that the issue need not worry the British public. Five years after both parties voted to join the US in the invasion of Iraq, the public should be deeply sceptical of this silence. Indeed, the US missile defence programme is setting back arms control before it has even been fully deployed. It has angered Russia and left many European states deeply concerned.

In order to press ahead with missile defence, the US unilaterally withdrew from the Anti-Ballistic Missile Treaty with Russia. Partly in response to the US decision to site missile interceptors and radar in Poland and the Czech Republic, Russia last year suspended the landmark Conventional Forces in Europe Treaty.

Russia has also threatened to pull out of other key treaties and to target its missiles on European cities. Czech and Polish public opinion is opposed to involvement in the programme.

Although their governments are supportive of missile
defence, there will be much opposition and debate before they sign up.

While marches and protests take place in Prague, there is a curious silence in Britain. The Government cautiously welcomed the programme back in 2002, and allowed Fylingdales to be used by the US. But it was a tentative welcome, and further debate was promised. However, by the time Menwith Hill was brought into the system last summer, the Government arrogantly and deceitfully made the announcement by written statement to MPs on the last day of the session. To date it has ignored all calls for a full Parliamentary debate.

Of course, neither Russia nor anyone else should have a veto over British security. In certain circumstances, a system that could provide Britain with protection from a hostile attack might be welcome. Indeed, there may come a time when the threat from missile attack is so acute and so immediate that we would need such a system. But in today's world, without multilateral agreement, even a supposedly defensive system can be perceived as a threat by others.

Indeed, Nato countries remain divided over the wisdom of missile defence. Canada has already refused to join the programme.

In April, Nato leaders will debate the subject. Before then, Liberal Democrats will be pushing Gordon Brown and David Cameron to justify their case for missile defence to the British people.

We will also look to the inspiration of politicians in eastern Europe who are
refusing to quietly accept pressure from the Bush administration. And we will continue to demand to know why although our Prime Minister gives unflinching support to the US on missile defence, Britain is not even consulted when the US talks to Russia.

A missile defence system might one day promote peace, but only if it is genuinely multilateral, with countries like Russia and China brought into a new partnership.

Such a broad-based system might reduce further the possibility of nuclear confrontation between established nuclear powers and guard the wider international community against the possibility of attack from the so-called "rogue states". But until such an agreement is in place, Liberal Democrats cannot support the dangerously destabilising "Son of Star Wars".

On the 25th anniversary of the "Star Wars" idea, it is worth remembering that even President Reagan at the height of the Cold War was prepared to share American technology with the Soviet Union.

It is a sad state of affairs to hark back to the comparatively co-operative days of the Cold War. Surely we can do better than that?

Edward Davey is the Liberal Democrats' foreign affairs spokesman.