British troops essential to Bush offensive

British troops will be crucial to the American attack on Iraq under US battle plans, despite suggestions by Donald Rumsfeld that the Americans can overthrown Saddam without them.

US commander General Tommy Franks has warned that the British must be in the main operation in Iraq, and not just left to clean up afterwards, which was Washington's thinking until the beginning of this month.

Franks wants troops of the 7th Armoured Brigade, the Desert Rats, to be given a pivotal role in the opening advance into Iraq from Kuwait and for the final attack on Baghdad.

Franks sees the British contribution of 40,000 service men and women as a necessity more than a luxury. Although more than 250,000 US forces have been mobilised under his command, he has only "about 120,000" US ground forces "ready to roll" for the invasion from Kuwait.

Key units such as the 4th US Infantry Division, the most technically advanced and best equipped of the US Army divisions, are not yet in place. The 4th Infantry and the tanks of the 1st US Cavalry Division were supposed to be launched into northern Iraq via Turkey. But the Turkish parliament said no, and the haggling is still going on with the new Turkish prime minister.

There have been similar difficulties with Jordan, though these have been less widely publicised. Both the US and the British wanted to use Jordan to mount operations to ensure that Saddam does not move mobile launchers to fire Scud missiles at Israel. But when the British wanted to base attack planes in the kingdom King Abdullah said no.

However, the Desert Rats, a force of nearly 15,000 troops with 150 tanks, artillery and more than 5,000 infantry troops, are ready for action and their speed has taken the Americans by surprise. The British now contribute more than a quarter of the effective firepower of the ground forces in Kuwait and the Gulf.

The Americans had intended to begin operations against Saddam in mid-February. Tony Blair warned President Bush that the bulk of British ground forces could not be ready, so they were left out of the initial plan of attack. But now British forces are ready in Kuwait - and are more ready than most of the Americans, except the 3rd Infantry Division, which has been training there since Christmas.

It is the readiness of this force - far more potent than the total British land force in the Falklands - that has made Tommy Franks and his planners rethink. According to some insiders, he has become a total fan of the British. He is now thinking of the 7th Armoured Brigade as the "hinge" on which his main attacking force will swing north in the initial advance from Kuwait. They could be sent forward to hold the key town of An Nasariyah. The British are then likely to make a "passage of lines" - one of the most difficult manoeuvres on the battlefield - to join the Americans in the final battle for Baghdad towards the end of next month.

With Turkey's refusal to allow in American troops for an advance on Baghdad from the north, the British 16th Air Assault Brigade is assuming a more prominent role. They give the Americans unexpected flexibility and are equivalent to some of the best US Special Forces.

The Royal Marines 3 Commando Brigade is now expected to help secure bases north of Basra on the Shat al Arab and the Tigris.

It looks very much like a campaign of several weeks, which could drag into May. It will be a complex piece of tactical choreography. Unless, of course, Saddam rolls over and surrenders or flees after the first 48-hour aerial bombardment of Baghdad. Not too many people are betting on that.