With thousands of nuclear missiles at his disposal, President Putin has no reason to worry about a handful of American interceptors that Washington wants to base in Poland as part of its “Son of Star Wars” defence system.

Even when the American missile defence programme is completed by 2013, there will still be only a total of 54 ground-based interceptors, in Alaska, California and Poland: enough to take out a theoretical combined ballistic missile threat from Iran and North Korea. Son of Star Wars, as currently envisaged, poses no threat to Russia’s nuclear status. Yet the Russians are clearly worried by the steadily encroaching presence of American weaponry on their borders.

They reluctantly swallowed Nato’s expansion into Eastern Europe. But American missile defence appears to be one step too far because it will involve two former Soviet Union satellite countries, Poland and the Czech Republic, becoming base nations.

Recently, to underline its anger, Moscow test-launched what it claimed was a “new” intercontinental ballistic missile, the RS24, and talked of scrapping the Start 2 arms-control treaty it signed with Washington. All the efforts made to reduce nuclear missile arsenals – Mr Putin and President Bush had an agreement to cut stocks to 2,000 each – looked set to be unravelled.

However, the Americans are not alone in building missile defences. The Russians have had a system around Moscow for decades and are now in the process of deploying the highly capable S400 missile around the capital and other key sites.

In the early 1980s when President Reagan first came up with his grand vision of a space-based antimissile shield, Moscow, along with most of Washington’s allies, dismissed it as unaffordable and unfeasible. However, when the US opted out of the 1972 AntiBallistic Missile Treaty in 2001 and started to scale down its programme to focus on accidental and rogue-state missile launches, Moscow got the message that the US had every intention of deploying a system, albeit limited, that would include European partners in a network of interceptors and radars. The Russians claimed that their nuclear sovereignty was being undermined.

The US has spent huge sums on missile defence – $105 billion since 1983 – and Congress has been asked to underwrite another $8.9 billion (£4.5 billion) next year. So far 16 missile interceptors have been based in Alaska, and two in California; and eight US warships, including three Aegis Class cruisers, carry 19 Standard3 interceptors between them. Some test firings have failed, but the notion that one missile – with no warhead – can hit another in space has been proven.

As part of a global missile-tracking system, the Americans have also established in the northern Pacific a mobile, ocean-going platform for an X-band radar that has a narrow tracking beam capable of spotting small objects in space. The platform, bigger than a football pitch, is staffed by a crew of 75. In the event of a missile attack, this radar system would need to be triggered by other radars, including the enhanced one at RAF Fylingdales in North Yorkshire, to help it to pinpoint incoming missiles. A second X-band radar is proposed for a site in the Czech Republic.

By 2013 the US hopes to have forty ground-based interceptors in Alaska, four in California and ten in Poland, as well as missiles on board warships. Other systems are also being developed, including an airborne laser fitted to a modified Boeing 747-400, and an interceptor called Thaad (terminal high-altitude air defence), which is a glorified version of America’s Patriot weapon.

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