So, what did we achieve? After four years and 174 dead, Britain's lead role in Basra is over

As responsibility for security is formally passed to theIraqis today, Raymond Whitaker examines what, if anything,our armed forces have accomplished there since 2003

The symbolism will be overwhelming. Today, at the last British military base in Iraq, Britain will formally hand over security in Basra, the last of the four Iraqi provinces for which it took responsibility after the invasion in 2003, to the local authorities. Bands will play; there will be a reading from the Koran; and speeches will declare this to be a historic moment.

In reality, however, nothing will change today. British forces stopped patrolling the rural areas of Basra province well before early September, when they finally quit Basra Palace, their last foothold inside Iraq's second largest city.

At that point, more than three months ago, the Iraqi army and police effectively took over security in the area which contains more than 70 per cent of the country's proven oil reserves and supplies 90 per cent of government revenue. Nor, after the ceremony, will hundreds of British soldiers be relieved of their duties in time to fly home for Christmas.

Prime Minister Gordon Brown has already outlined the timetable: the 4,500 troops remaining at the contingency operating base, known as the COB, at Basra airport will gradually be reduced by 2,000 over the first three months of 2008. Those left will continue training Iraqi forces and maintaining an "overwatch" role, ready to intervene in an emergency if asked to by the Iraqis.

Despite their retreat from the streets of Basra, British forces are not completely out of danger. Last week Guardsman Stephen Ferguson of the 1st Battalion, the Scots Guards, was killed when his Warrior armoured vehicle slid into a canal. He was the 174th British soldier to die in Iraq since the invasion. And, though the British force has not suffered a death from "hostile activity" since September, rocket and mortar attacks on the COB continue. Many of the troops still sleep in tents, with blast walls made of breeze-blocks or sandbags surrounding each bed, so that, while a direct hit would be fatal, the rest of the tent's occupants might escape without serious injury.

All this is out of sight and out of mind as far as Basra's inhabitants are concerned. "We do not see them [British troops], and we do not know what they are doing," said Abdullah Haji, a 52-year-old electrician. "We do not know how many are left in Basra, or how much longer they will be staying here. Now we have our police and army, and we also have the militias. But I do not want to talk about the militias."

Mr Haji's nervous comments go to the heart of the dispute over what, if anything, Britain has achieved in Iraq. No weapons of mass destruction were ever found, of course, but four and a half years after Tony Blair proclaimed "Iraq will be a significantly better place as a result of the action that we have taken", can we claim any success? Or have we allowed politicians and military commanders to redefine the mission in such a way that they can deny it has been a complete failure?

"Whatever mistakes have been made," Mr Blair was saying in mid-2004, "... let us be pleased that Iraq is liberated." But only two years after the invasion, British officials in Basra were emphasising, off the record, that it was unrealistic to expect that south-east Iraq would ever be like south-east England. It had always been a lawless, violent place, where tribal rivalries, smuggling and bloody vendettas were a way of life.

The next stage in this lowering of expectations came in October last year, when the head of the Army, General Sir Richard Dannatt, said that the presence of British troops in the area was "exacerbating" the situation, and that they should leave "soon". In the wake of General Dannatt's outburst, and especially after British combat deaths rose this year to their highest total since 2003, the military authorities began stressing that 90 per cent of the armed attacks in Basra were directed against British troops. Those who predicted that a British withdrawal to barracks would see an upsurge in violence would be proved wrong, they said.

Comments last week by the British military spokesman in Basra, Major Mike Shearer, followed this script faithfully. He said British troops had pulled out of Basra city because their presence was felt to be "provocative", adding that attacks had dropped dramatically since September. He accepted that the province was not "fixed", but went on: "We never pretended that we were going to hand over a province that had a white picket fence around it like a scene from The Stepford Wives."

Others, however, see an alternative reality. One Basra resident, Ahmed Hussein, welcomed the British withdrawal from Basra Palace purely because it had deprived the militias of a target. As they exchanged fire, he said, "they both used to miss, and a lot of innocent people got killed". But Peter Harling, Iraq project director of the International Crisis Group, which earlier this year published a damning report on Britain's occupation of Basra, said the British would have been unaware of these casualties.

"The only violence the British forces know about is that directed against them," said Mr Harling. "They have never monitored violence against Iraqi civilians, who have been left exposed. They have no protection whatsoever in their daily dealings with the militias and criminal gangs who dominate Basra."

Claims that General Jalil Khalaf, a new police commander sent in from Baghdad, had had some success in bringing order were sceptically treated by Mr Harling. "It would take a major showdown, of the kind the British never sought, to achieve any sort of order," he said. "The militias haven't confronted the Iraqi authorities, because they don't consider them a major threat. At the moment, despite regular clashes, there is a precarious working relationship among the militias, but it is a balance of terror."

Extreme Islamists have brutally enforced their vision of proper behaviour, banning activities which used to be normal in what was once a sophisticated city, such as music and dancing. In the past three months, 42 women have been reported killed for wearing make-up, or failing to don the hijab headscarf. Sama, a 24-year-old student, said ,"All my family, my friends, go out now with their heads covered. We know of girls who were killed because they did not listen to warnings. There was one woman who was accused of having an affair, and they took her away. No one has seen her since. Before the war we could all go out without our heads covered. We even went out in mixed groups, but that is no longer possible."

A poll of Iraqis in Basra, commissioned for BBC2's Newsnight last week, showed that a huge majority 86 per cent believed that the presence of British troops had had a negative effect on the province. More than half, 56 per cent, thought it had increased the level of militia violence, and nearly two-thirds wanted the British to depart the region altogether.

Was any other outcome ever possible? Toby Dodge, an Iraq expert at London University and the International Institute of Strategic Studies (IISS), doubts whether foreign forces could ever have achieved the Washington neocons' vision of spreading peace and democracy in the Middle East through regime change in Iraq. But he is particularly scathing about British policy in Basra, saying: "It was doomed from the beginning, because we never had anything like enough troops or resources on the ground. Since we were never able to help the ordinary people of Basra, we simply set the policy to fit the resources."

Even within the narrow definition of success for British forces, however the absence of mass violence - the triple bombing that took place last week in Amara was an ominous sign. One of the worst attacks in months, it killed at least 40 people and wounded more than 150 in an area where security responsibilities were handed over to the Iraqis earlier this year. Most analysts blamed militia rivalries, and Christopher Langton, senior fellow at the IISS, warned: "This could be replicated in Basra."

But even if there were to be a similar upheaval as powerful forces struggle for the spoils in a city which is the hub of Iraq's oil industry, Britain would insist that it was a problem for the Iraqis themselves to solve. With only 2,500 troops remaining, there are questions whether they would be able to do much more than defend themselves, and the hope is to have most of them home by the end of 2008.

At American urging, enough forces will be kept in place for the time being to secure Basra airport and the supply lines from Kuwait to Baghdad and the surrounding provinces. This may mean that some British troops remain in Iraq for several years to come. But the plain truth is that the British mission there came to an end for all practical purposes several months ago, when Operation Sinbad, a last attempt to seize back the initiative in Basra from the militias, was called off. It is a long way from the crusading zeal of 2003.

Voices from on and off the battlefield

Even among the many who believe we should never have gone into Iraq, there is the uneasy feeling that the manner of our leaving is less than honourable:

'We are very glad the British got rid of Saddam, but things are really bad here'

Abdullah Haji, 52, Basra technician

'I have much less freedom since the British came than before'

Sama, 24, Basra student

'This [withdrawal] is long overdue, for all the good the Iraqi adventure has done'

Peter Kilfoyle, former defence minister

'It is the start of a very difficult period of confrontation with Iran'

Patrick Mercer, Tory MP and former army officer

'If we had left earlier, we would have left it in a much better state'

Rose Gentle, Whose son, Gordon, died in Iraq

'Was it worth all the bloodshed? I don't think it was'

Field Marshal Lord Bramall, former chief of defence staff