The first of the jets, and their six crew, touched down in mid-afternoon under bright skies at RAF Leuchars, on Scotland's North Sea coast, amid cheers from waiting wives and children.

Officials in London announced just hours earlier that, two days after the fall of Baghdad to US forces, Britain would gradually start withdrawing forces, starting with naval ships and aircraft.

"This is by no means the beginning of a full scale reduction," Armed Forces Minister Adam Ingram told a press conference.

"Our commitment to Iraq's future is undiminished and we are in the very early stages of beginning to look at the post-conflict phase," he said.

"It would not make sense to keep personnel in the region any longer than is necessary. Some have already returned and some will return shortly."

A Ministry of Defence spokesman said the destroyer Liverpool and frigate Marlborough would proceed to southeast Asia for long-planned exercises, while the aircraft carrier Ark Royal would "soon leave the area" for home.

"We envisage a number of helicopters and aircraft coming back in the next few days," the spokesman told AFP.

He also said that Britain would withdraw a field hospital as well as the Royal Fleet Auxiliary ship Argus, a helicopter-ready floating hospital for combat casualties.

Prime Minister Tony Blair ordered 45,000 soldiers, sailors and airmen, 120 tanks, a naval task force led by the Ark Royal, and more than 100 aircraft to the Gulf to join the US-led war in Iraq that began March 20.

The deployment included almost one-quarter of the entire British army, concentrated in the south of Iraq, securing the country's second city of Basra, oil fields and the Gulf port of Uum Qasr.

Defence Minister Geoff Hoon said: "As the pattern of coalition operations in Iraq changes, it will be possible for a number of units to proceed with other tasking or return to the United Kingdom.

"Significant maritime forces will remain in the Gulf to continue important continuing tasks, including mine clearance operations, logistic support and force protection," he said in a written statement to the House of Commons.

"We also continue to keep our requirements in the land and air environments under review."

The Royal Navy's chief of staff Admiral Alan West said it was always the intention of British commanders to draw down their forces as soon as possible.

"We always said that when forces were not required, not essential for operations, we would pull them back, not least to give the people a break," West said.

Some British personnel have been in the area for as long as 10 months, he said, adding: "That's quite a long time. We need to recharge these people's batteries."

He confirmed that the Liverpool and Marlborough would be proceeding to southeast Asia, along with the fleet auxiliary ship Grey Rover, because they were "no longer essential for operations."

"On the maritime side, almost inevitably, because we arrived there, kicked the door open and allowed things to happen, (warships) are the ones generally who will be coming back quicker, regenerating, and getting themselves ready to go again," he said.

SPACE.WIRE