The sign outside RAF Menwith Hill in North Yorkshire bears the proud motto "Defend and Strike" but yesterday it could hardly be said that the base lived up to those high ideals.
This is one of the most sensitive surveillance stations on the planet with huge golfball-like structures called radomes springing from the rolling countryside which possess the technological capabilities that George Bush so craves if his proposed missile defence system – "Son of Star Wars" – is to work.
To the casual observer, it might seem that Menwith Hill's intelligence-gathering role would make it invulnerable to a surprise attack, but yesterday it didn't appear very intelligent at all after 100 Greenpeace activists drew up in three coaches, put on rubber suits shaped like missiles and simply marched in to the deafening sound of music from Star Wars and Mission Impossible.
Within minutes, 16 of them had chained themselves to the top of a water tower, 23 more had climbed on to the roof of another building, two had been arrested for painting "Stop Star Wars" on a base installation. The issue of missile defence, so conspicuously absent during the election, was back on the agenda.
If it were not such a serious issue, yesterday's raid might almost have been funny. According to activists, when they arrived in their coach at the front gate, some seven miles outside Harrogate, at 5am, there was just one guard who tried in vain to halt the tide of walking rubber missiles and flag-waving campaigners dressed in latex George Dubya costumes.
Meanwhile, taking advantage of the chaotic diversion at the front gate, two coaches dropped off more activists at two locked entrances further to the west. They scaled the gates and two razor-wire topped fences to gain access to the base.
"It was very funny and it does raise questions about the kind of security they have here," said Louise Edge, a Greenpeace spokeswoman. "But our main concern was more serious; to bring people's attention to the dangers of Bush's Star Wars programme. If it wins Britain's backing, then Menwith Hill will be used and will make Britain a target."
So what are the President's plans? Mr Bush and the hawks among American republicans want to build on the work started during the Ronald Reagan era when he planned to destroy enemy missiles in space using ground detectors, lasers and anti-missile missiles. Mr Bush's "National Missile Defence" system is more limited but would still cost $60bn (£42.7bn) to develop – and even then many experts doubt it could work.
Nevertheless, Mr Bush claims the threat from "rogue states" is such that he wants to go ahead. Under his proposals, five American early warning stations will be needed including two in Britain, Menwith Hill and Fylingdales near Whitby in North Yorkshire.
Two stations in Britain would make it a target, but the anti-Star Wars arguments go much further. "It would trigger a new nuclear arms race with countries like China, which would feel it would have to go for more missiles if its own deterrent were to be effective," said Stephen Tindale, director of Greenpeace UK.
"And it would make Britain a sitting duck. Anyone who wanted to attack America would have to attack Menwith Hill and Fylingdales first." In fairness, the Americans have said any shield would cover its allies, too. As yet, Britain has not taken a stance on the issue but Mr Bush is due to visit Downing Street later this month, and it is thought likely that Son of Star Wars will be on the agenda.
Until then, Greenpeace intends to continue with campaigns and actions planned with the kind of military precision so sadly lacking from the armed forces at Menwith Hill yesterday.
"It did take a lot of planning – about three or four months," said Stan Vincent, Greenpeace's director of logistics. "We have a stable of people we can call on who have undergone non-violence training courses, and we began calling on them some time ago. We don't use the same telephone line repeatedly or e-mails or mobile phones for obvious reasons. Instead, we sent out letters giving details of risk – both physical and legal – and a time and place to rendezvous if they wanted to join in."
Last night, climbing experts flown in from Scotland were helping MoD police cut free and bring down activists safely but the police were refusing to say much about the operation or the earlier embarrassing invasion.
There is little doubt, however, that security will be stepped up at Menwith Hill and Fylingdales, particularly in advance of Mr Bush's visit.
National Missile Defence is Greenpeace's new bogeyman, one that will be attacked at every opportunity in as high-profile a manner as possible.