London - The timely announcement that British troops will leave Iraq six years after the US-led invasion and the toppling of Saddam Hussein brought little Christmas cheers to Britons Wednesday.

While Prime Minister Gordon Brown will be hoping that closing the chapter of Iraq might add to the publicity surge he is currently enjoying, the war-fatigued British public and the military are apprehensive about an increased military involvement in another conflict: Afghanistan.

By the end of July next year, when the remaining 4,100 British combat forces are finally due to leave their barracks on the outskirts of Basra in southern Iraq, their ceremonial exit is likely to be accompanied by doubts over whether they achieved what they set out to do.

Since the March 2003 invasion, when Britain sent 46,000 men and women to invade Iraq alongside the Americans, troop numbers - and the popularity of the cause - have been in steady decline.

After initially patrolling in "soft caps" - as opposed to hard helmets - and priding themselves on talking to local leaders and playing football with Iraqi boys, British troops made a hasty overnight exit from their Basra Palace headquarters in September 2007, to the safer outskirts by the airport.

With almost daily roadside bomb attacks on British forces by insurgents, the rise in casualties had become intolerable. The troops' reputation was also tainted by abuse and torture allegations.

At home, the reputation of Brown's predecessor Tony Blair, who stood "shoulder to shoulder" with George W Bush in the invasion, lay in tatters.

When Brown took over in June 2007, he made the gradual withdrawal from Iraq one of his key priorities.

"We leave Iraq a better place," he said Wednesday, pointing to democratic and economic progress and the advances made in training Iraqi police and military forces.

Brown hopes that by bringing the troops home from a conflict that, ultimately, proved militarily "unwinnable," he can enhance his standing at home, which has recently been boosted by his handling of the financial and economic crisis.

But the British public, and especially the 178 families who lost loved ones in Iraq, remain apprehensive about what lies ahead.

An ICM opinion poll, published in mid-November, showed that 68 per cent of Britons want their troops out of Afghanistan within a year, and that the anti-war sentiment is especially strong among the younger generation.

Additionally, the top brass of the armed forces have made clear that there can be no "straight transfer" of troops from Iraq to Afghanistan, due to "overstretch" - the sheer exhaustion of personnel and the lack of equipment.

Against the background of 133 military fatalities in Afghanistan so far and studies which appear to confirm a steady advance of Taliban forces, Brown is likely to have a battle on his hands in winning public backing for an expanded role in Afghanistan.

British concerns about public opinion are in direct contrast to the call by US president-elect Barack Obama for a troop surge in Afghanistan.

Obama's plan to send an additional 20,000 US troops to Afghanistan - and possibly some 5,000 to the volatile southern province of Helmand - have so far met a reserved response in London.

Reluctantly, Brown recently committed a further 2,000 troops - in addition to the 8,400 already in Helmand. But he has repeatedly urged other European NATO allies to step up their contingent in what London calls "fair burden-sharing."

For the British military, a "one-for-one transfer" from Iraq to Afghanistan is an impossibility, the head of Britain's armed forces, Air Marshal Jock Stirrup, has publicly warned.

"I am a little nervous when people use the word 'surge' as if this were some sort of panacea," said Stirrup. "It's crucial that we reduce the operational tempo for our armed forces."