MILITARY units based in the region could be pared down or axed altogether under a radical overhaul announced yesterday of the way British forces go to war.

In a statement to the House of Commons, Defence Secretary Geoff Hoon announced proposals included in a Defence White Paper, drawn up while the UK's Armed Forces have been operating in Iraq.

And, although no specific units have been told they are in the firing line, the Army, Royal Navy and Royal Air Force have been warned to expect another round of cuts.

The White Paper's recommendations are based on the premise that future wars will not be fought by opposing forces on a broad front, with attrition deciding the outcome.

Terrorism and the possibility that nuclear weapons could fall into the hands of a rogue state are now seen as the primary threats to world peace.

As a result, the White Paper suggests modern armed forces should be readied for "multiple, concurrent, small to medium-sized missions".

Lightly-equipped, versatile, rapid response forces are seen as the way forward - at the cost of heavy armour and artillery.

Versatility will also be the key in the air, with single-role fast jets the most likely casualties, while older Navy vessels could also be made surplus to requirements.

Mr Hoon said: "We have been successful in recent military operations because we have always looked ahead at the capabilities we need for future challenges.

"The proliferation of weapons of mass destruction and the threat posed by international terrorists, coupled with the consequences of failed or failing states, present us with very real and immediate challenges."

Mr Hoon confirmed British troops would still be expected to deal with peace-keeping missions and be asked to tackle large-scale operations such as Iraq. And he said that, in future, British troops would always have to work closely with the US.

"Resources must be directed at those capabilities that are best able to deliver the range of military effects required, while dispensing with those elements that are less flexible," said Mr Hoon.

"It has historically been the fashion to measure military capability in terms of the weight of numbers of units and platforms - of ships, tanks and of aircraft.

"That might have been appropriate for the attritional warfare of the past but, in today's environment, success will be achieved through an ability to act quickly, accurately and decisively, so as to deliver military effect at the right time."

Mr Hoon later appeared to acknowledge that his plans meant Britain could take part in a major military operation in future only if it was fighting alongside the US.

He told Channel 4 News: "If we had the kind of large-scale conflict we have seen in Iraq, we assume that we would only be operating alongside the US, as a close ally. But there are many other kinds of operations we would and could and do engage in without the US."

The White Paper concludes that, since the end of the Cold War, the need to hold a large number of troops in reserve in the UK to combat a direct threat to the nation's shores has receded.

"Our priority must now be on providing the capabilities to meet a much wider range of expeditionary tasks, at a greater range from the UK and at an ever-increasing tempo," said Mr Hoon.

"Counter-terrorism and counter-proliferation operations in particular will require rapidly-deployable forces able to respond swiftly to intelligence and achieve precise effects in a range of environments."

Shadow Defence Secretary Nicholas Soames said Conservatives supported the fundamental thrust of the White Paper.

But he emphasised his party still had grave reservations about the Government's defence budgeting.