GENERALS RARELY make off-the-cuff comments. Everything they say is measuredandcarefully controlled; after all, lives could depend oneverywordand nuance. That's why senior commanders and politicians on both sides of the Atlantic sat up and took notice when General Jack Keane, formerly of the US army, accused his opposite numbers in the British Army of "general disengagement from the key issues around Basra".

It was not just that Keane was engaging in a high-profile spat with his country's closest allies in the coalition forces occupying Iraq. After all, neither the Americans nor the British have been shy about making critical remarks about the performance of each other's forces in Iraq and Afghanistan. Three years ago, great resentment was caused by the leaking of a Foreign Office memo criticising the US Army for its heavy-handed approach topeacekeeping in Iraq and the resentment resurfaced on Fridayafterthreesoldiers from the Royal Anglian regiment were killed when a US fighter-bomber mistakenlybombeda British position in southern Afghanistan.

Britishofficers had already voiced angeraboutUSairstrikeskilling civilians and this kind of criticism does not go down well with the Pentagon.

Rather, the general's comments mean it is now open season on the future military policy of coalition forces in Iraq. Even before Keane made his statement it was no secret that Britain would be giving up its main base in the city at Basra Palace and soon reducing its troops to 3000 to protect the air bridge at the main airport. Following a visit to the area, Keane made his position perfectly clear and, considering his close links with the White House, it seems likely that his views are shared by President George Bush and his administration.

"The Brits," said Keane, "have never had truly enough troops to protect the population." So sure is Keane the British are about to pull out of Basra that he has recommended to the Pentagon that the US Army deploy a brigade group to replace it in case the insurgents take advantage of any power vacuum.

"That situation could arise if the situation gets worse in Basra if and when theBritishleave,"hesaid."Nowthe situation has changed in the south, it is considerably worse, certainly with the kind of gangland warfare that is preying on the people in the south."

Curiously, his words would be echoed by most senior British commanders with experience of serving in Basra. Long gone are the days when foot patrols could wear soft hats on the street in the wake of the invasion in 2003. Today the garrison is under constant attack from rival Shia militias and it's widely acknowledged that the British soldiers are no longer part of the solution but have become a major partoftheproblem.Casualtiesare suffered on a regular basis - in addition to the 168 who have been killed since the invasion, scores have been wounded or are suffering from illness - and troops can only venture out of their bases in heavily armoured vehicles. Last week, Kevan Jones, a Labourmember of the Commons defence committee who recently spent time in Basra, described the situationfacingtheBritishas"aforce surrounded like cowboys by Indians".

It is an apt metaphor but it goes further than a comparison with western movies. The garrison in Basra is not just under constant attack from incoming mortar and rocket fire, it also has to contend with the enemy within. Despite all attempts to counter the threat, Shia groups have managed to infiltrate the fledgling Iraqi security forces and the upper echelons of the local police force are riddled with corruption. That kind of infiltration has hampered efforts to keep the peace and has created difficulties in maintaining security. If plans are shared with the Iraqis, as they should be if there is to be a handover next year, the odds are they will be compromised. The result is that senior commanders now feel any benefits are now being cancelled out by the very presence of the British Army.

"Anhonestassessmentofour position in Basra would begin by stating that force protection is now our priority," said a senior British military commander who has served in Basra. "The days of mingling with the locals have long gone and there is a very real danger we could find ourselves isolated by the fighting between rival militia groups.Ithink everyone acknowledges that we have done as much as we can with limited resources and that the time has come to concentrate on the far more challenging task facing us in Afghanistan."

This may not be what the US commanders want to hear, but it is looking increasinglylikelythattheBritish government will be taking that option. For the time being, prime minister Gordon Brown is keeping his cards close to his chest. He did enough during his recent visit to the US to suggest the special relationship is intact but he isalsolisteningtowhatsenior commanders have to say and a consensus is growing that there will have to be a readjustment of troop levels sooner rather than later. That much became clear when the chief of the defence staff, Air Marshal Sir Jock Stirrup, responded to Keane's attack with an assertion that the British presence in Basra was not perfect but not as bad as the general had suggested.

"Our mission was not to make the place look somewhere green and peaceful because that was never going to be achievable in that timescale and, in any case, only the Iraqis can fulfil that aspiration," said Stirrup.

For all that there have been regular spats between the two sets of soldiers, the British presence is still highly valued by the US Army in Iraq. British officers serve on the staff of General David Petraeus, the head of the Multi-National Force - Iraq (MNF-I), and at special forces level there is a good deal of co-operation. It is also true that the British presence in Basra is tactically important as it safeguards the main entrepôt and is the beginning of the main supply route heading north towards Baghdad. Then there is the political perception. As long as British forces remain in Iraq, they make it easier for Bush to sell the war at home, and serve as a bulwark to the noisy demands for a significant reduction in US troop levels.

On this point the president is already in a tight corner. Last week, he caused delight in Democratic circles by invoking a comparison with Vietnam and then suggesting that the Iraqi prime minister, Nuri al-Maliki, was not fit for office and might have to be replaced. His cause was not helped when Senator John Warner, a prominent Republican and a former chairman of the Senate's armed services committee, demanded that the US should cut its garrison as the Iraqi administration had failed to make any progress in dealing with the country's many problems. Warner's words were given substantial reinforcement when Marine General Peter Pace, chairman of the Joint Chiefs of Staff, recommended that a draw-down in US troop levels should begin as early as next year.

In an attempt to regain the initiative, Bush will use an address this Tuesday to the Veterans of Foreign Wars association toreinforcetheideathattheUS commitment to Iraq is non-negotiable and that troops won't be withdrawn during his watch. With his presidency due to end next year, that might not be much of a promise, and despite the firm words from the White House there have already been subtle shifts in US policy.

Next month, Petraeus will give his much-anticipated report on the results of the US Army's move against the insurgents in the Baghdad area and while this will be an upbeat account highlighting success in Anbar province - where Sunnis have been recruited to fight against al-Qaeda cells - there will be less emphasis on the need for democracy. OneofPetraeus'scommanders, Brigadier-General John Bednarek, has already gone on record as saying that "democratic institutions are not necessarily the way ahead in the long-term future". Even US ambassador Ryan Crocker has admitted that the US is now "pursuing less lofty and ambitious goals than was the case at the outset".

If that is the case it could be good news for al-Maliki, who was given a torrid time by Bush's assessment that his job was on the line. The president's words were unhelpful on two counts. Not only did they undermine al-Maliki's position but they seemed to suggest the job of the Iraqi prime minister was in Bush's gift - hardly the best advertisement for the US commitment to introducing the multi-party, multi-ethnic government promised from the outset of the campaign to depose Saddam Hussein.

However, for all the rights and wrongs about how to deal best with al-Maliki, it is clear the US has lost patience with the Iraqi leadership. In the wake of Bush's criticisms,theNationalIntelligence Assessment released a damning report about al-Maliki's failure to quell sectarian violence and to promote political unity. A source close to the report admitted it makes gloomy reading, not least because it warns that Iraqi dissident groups might attempt a "mini Tet" - another reference to the Vietnam war when the Viet Cong andNorthVietnammounteda co-ordinatedoffensivein1968to undermine US support oftheSouth Vietnamese government.

That really would be a nightmare scenario. First, it would make a self- fulfilling prophecy of Bush's comparisons with Vietnam and, second, it would be a sure sign the US's Baghdad surgehadfailed.Iftheinsurgents decided to take advantageoftroopwithdrawals by combining and mounting simultaneous attacks in the main cities Iraq would be facing disaster.

As it turned out, the 1968 Tet offensive ended in failure for the communists but the perception was cementedthattheUSand South Vietnam had suffered a major setback. Although from a military point of view there was no defeat, the Viet Cong and the North Vietnamese had won a huge propaganda coup and it was the beginning of the end. Five years later the US was on its way out of Vietnam.

"Both Britain and the US are in a double-bindinIraq,"claimedthe British military source. "We started the war and while it is clear that there is little point in remaining in the country indefinitely, simple morality tells us that we have a responsibility to the people of Iraq. We're damned if we stay and damned if we leave."