From the link supplied by Stu, to explain why he thinks that the UK does not have an independent nuclear deterrent.

The article points out that although we have our own submarines and our own warheads the missiles that carry those warheads to their targets are American, built by Lockheed-Martin. The weapon is therefore not totally independent according to the writer of the article.

The article does refer to what the writer calls "Operational Independence" - which is really all you require to have an independent deterrent.

"Under the terms of a missile lease arrangement, the United States does not have any veto on the use of British nuclear weapons, which the UK may launch independently" - Ministry of Defence Statement

The writer refers to the common pool of missiles kept and maintained by Lockheed Martin across in the USA. What the writer does not say in his article is that 48 of those missiles are either in the UK at RNAD Coulport or loaded in the "at sea" SSBN, 16 missiles used to be carried but that number was reduced to 8 missiles carrying 40 warheads in 2010.

The writer towards the end of his piece then gives away his lack of knowledge by stating the following:

"We are told if a UK prime minister presses the codes for launch from a Vanguard then Washington cannot do anything."

What he is describing here is the American PAL system. No such link exists in the British system:

"At the end of the Cold War, the U.S. Navy installed devices on its submarines to prevent rogue commanders from persuading their crews to launch unauthorised nuclear attacks. These devices prevent an attack until a launch code has been sent by the chiefs of staff on behalf of the U.S. president. The Ministry of Defence chose not to install equivalent devices on Vanguard submarines on the grounds that an aggressor might be able to eliminate the British chain of command before a launch order could be sent."

There are no codes that can be sent by the Americans to self-destruct missiles, the missiles carried on the RN's SSBNs rely on no external system for guidance so cannot be redirected once launched.

Don't know about you Stu, but that seems pretty independent to me.