The proposed force would be drawn from volunteers among the existing 50,000 or so armed forces reservists.

New reaction force

6,000 troops involved Largely from 50,000 reservists Will aid emergency services in the event of terror attack Chemical, nuclear or biological attacks not ruled out Mobilisation within hours of attack

They would be on stand-by to help emergency services in the aftermath of all kinds of terrorist strikes - including chemical, biological or even nuclear attacks.

But Conservative defence spokesman Bernard Jenkin cast doubt on whether the plans went far enough.

"We are not dealing with the IRA who are a terrorist organisation who do not like to kill themselves...

"We are talking about terrorists who are prepared to go to any lengths."

'Rebalancing'

Under the proposals volunteers for the force would remain with their normal units and be earmarked for availability in the event of a terrorist strike.

The TA has 40,000 members

Receiving five or six days' extra training a year, they will be available to help police within a few hours of an attack.

They will carry out operational tasks such as searching for survivors, securing water supplies and communications, dealing with mass casualties and organising transport.

Defence Secretary Geoff Hoon told the BBC that the UK had set out to learn lessons from the 11 September atrocity.

"The first job of government is to ensure the safety and security of its people and this is part of the lessons that we are learning, specifically in relation to the role of the reserves and what they can do," he said.

Earlier this year the MoD said Territorial Army volunteers should play an expanded role to reduce the pressure on the regular forces.

It said that as increasing numbers of British soldiers were being deployed abroad on the "war on terror", new ideas were needed for homeland defence.

The volunteer reserves could play an important role in meeting the challenges posed following the terrorist attacks in the United States

Geoff Hoon

The consultation paper foresees a greater role for the armed forces in civil contingency planning.

The predominantly Territorial Army 2 Signal Brigade would be equipped with compatible radio systems to those used by the police and civil emergency services.

But a new force would only be deployed in the event of "wholly exceptional" circumstances of a major terrorist attack.

Such attacks were acknowledged in the consultation paper as likely to be "infrequent" although their unpredictability and the chances of multiple attacks to maximise impact were not ruled out.

"Chemical, biological, radiological or even nuclear devices cannot be ruled out," the paper warned.

"Although the international response to the September 11 attack may help to reduce the likelihood that these might be used, some terrorist groups will certainly be interested in causing an equivalent, mass casualty effect."

Change of thinking?

While reservists are clearly seen to have an important future role, defence sources stressed they would form just one part of the UK's military response.

The full resources of the regular forces would still be available.

The announcement shows a change of heart since the 1998 strategic defence review when the government thinking involved scaling back reserves by nearly a third - a point seized on by Mr Jenkin.

He also said that no new money appeared to be forthcoming for the force although he refused to say what funds a Conservative government might make available.

"The present commitments of the armed forces already outstrip resources - will this simply add to overstretch?" he asked.