Geoff Hoon has said that Britain would consider using nuclear weapons if a country used weapons of mass destruction against British troops.

Giving evidence to the Commons defence select committee, the defence secretary said he identified Iraq, Iran, Libya and North Korea as countries that may not consider this a threat.

"There are clearly some states who would be deterred by the fact that the UK possesses nuclear weapons and has the willingness and ability to use them in appropriate circumstances," he said.

"States of concern, I would be much less confident about. Saddam Hussein has demonstrated in the past his willingness to use chemical weapons against his own people.

"In those kinds of states, the wishes and needs and interests of citizens are clearly much less regarded, and we cannot rule out the possibility that such states would be willing to sacrifice their own people to make such a gesture," he said.

"They can be absolutely confident that in the right conditions we would be willing to use our nuclear weapons. What I can not be absolutely confident about is whether or not that would be sufficient to deter them from using a weapon of mass destruction in the first place," he added.

Son of Star Wars

The committee was also given a statement on the possible co-operation with the United States on a missile defence system, known as "son of Star Wars", but refused to divulge the extent of UK involvement so far.

"We have so far received no requests from the United States for the use of sites in the UK for missile defence purposes. We do not know exactly what might be involved in such requests nor when they might be made," said Hoon.

"If we are asked to make such a decision we will of course do so on the basis of our own national interest."