Washington is set to make a formal request as early as next week to incorporate the Fylingdales radar station in North Yorkshire into the system.

Senior US defence officers have already visited the site.

But Mr Savidge has issued a warning over the system which has been nicknamed Son of Star Wars.

He said: "I think this is a very dangerous system in a number of ways. I think it is set up against a risk which is a very low one; I think that the system itself is doubtfully technically feasible; it potentially undermines arms control." Washington says the multi-billion dollar system, which is still in development, would protect the US and her allies from missile attacks by rogue states like North Korea.

But Mr Savidge said: "I think there is a potential, particularly in southern Asia, that it could encourage China to expand its nuclear forces more than it otherwise would, which could in turn encourage India and Pakistan to increase their forces.

"I think there is also a danger that it will encourage an increasingly gung-ho attitude in the US to starting wars in the belief that they would be invulnerable from response.

"I think we do have an absolute right to say that British foreign policy has to be British and not just a foreign policy, dictated by another country."