Greenpeace activists ended an occupation of a military eavesdropping base last night after their successful storming of the facility for the second consecutive day sparked calls for the Government to tighten security.
Twenty activists climbed over fences at RAF Menwith Hill in North Yorkshire yesterday to protest at the base's proposed role in President George Bush's "son of Star Wars" missile defence system.
Only the day before, Ministry of Defence police were caught unawares when more than 100 protesters dressed as missiles ran through the front gates. About 40 scaled a water tower, a control building and communications masts.
Last night the final two protesters, Richard Watson and Al Baker, descended from a radio mast after a 15-hour occupation and voluntarily surrendered to MoD police.
Iain Duncan Smith, the Tory defence spokesman, said security at the base should be beefed up and he urged the Government to back Mr Bush's plans for a shield to defend against attacks from "rogue states".
"The Secretary of State for Defence needs to explain how this hugely important and sensitive MoD facility had such low levels of security," he said. "It has now been breached by campaigners two days running. The Government must tighten up security ... and get off the fence and support the Americans by calling for a Nato-based missile defence programme to cover European countries, including the UK."
Mr Bush's proposals have concerned China, Russia, and some European Union countries. Fears have been raised that the missile defence plan could cause a new arms race.
Stephen Tindale, the director of Greenpeace UK, said: "If America builds a shield ... then other countries will feel they have to build enough missiles to overwhelm the system; otherwise their own deterrent would be worthless. That could result in countries like China building more weapons, while America, feeling invulnerable, could become more aggressive in its foreign policy."
The US says the shield would defend against missiles from "rogue states". It also says that countries such as Britain, whose listening bases at Menwith Hill and Fylingdales also in North Yorkshire would be vital to the system, would be covered by it.Reuse content