Britain asked for 4,000 more troops

Britain is being asked by the Americans to provide at least 4,000 extra troops to help protect extended supply lines for forces now in Iraq.

They would also help restore law and order once Baghdad has fallen, not only in the capital but all over the country.

The issue of reinforcement is likely to be discussed at Tony Blair's meeting with George Bush at Camp David today. So far the Government and Britain's senior officer in the Gulf, Air Marshal Brian Burridge, are saying that the issue of reinforcements is not under consideration - though Geoff Hoon, the Defence Secretary, said on Monday that it might have to be considered later.

The vulnerability of hugely long supply lines - more than 200 miles from Kuwait to central Iraq where British and American forces are forming up for the final battle in Baghdad - is becoming a security priority for the coalition forces.

The first US troops to be taken prisoner were logistics and repair troops, one a reservist, told to set up a repair station on the road north at Nasiriyah. They were given very little force protection, and they had no escorts.

The hit-and-run ambush tactics of guerrillas and militias of the Ba'ath party and the Fedayeen will make it necessary to escort large supply convoys for some time to come.

Britain's forces are already overstretched by the Iraq operation and the need to provide 16,000 to 19,000 personnel at home as cover for the firefighters' dispute - although these are not likely to be needed as the dispute winds down. Britain could send a large brigade of four or five infantry battalions - at a pinch. It would need a brigade headquarters to command it - probably 19 Brigade based at Catterick or the 4th Armoured Brigade based in Germany.

Most of the new forces could be flown to Kuwait immediately - though it might be hugely expensive to charter aircraft and ships to move their vehicles and equipment to the Gulf. It cost £50,000 a round trip to hire each of the huge Ilyushin transport planes to move British peacekeepers to Afghanistan.

The mounting cost of supporting a force of nearly 50,000 British service personnel over the next few months must be worrying the Treasury. With George Bush asking Congress for some £50billion for the Iraq campaign, costs are bound to rise for the British effort.

With a cost of roughly £45,000 per soldier per month on operations, the bill for the British taxpayer could be well over £5billion by June. This will be another reason for Tony Blair's reluctance to send in reinforcements unless George Bush twists his arm - which he is expected to do.