Robert Fox: What Blair must tell Bush

Plain speaking is needed when the Prime Minister goes to Washington this week

Where do we go from here? The "coalition" forces are getting bogged down in Iraq, parts of which have slipped from the US's grasp. Comparisons are being made with Vietnam. A new chapter has been opened with the taking of hostages. George Bush and Tony Blair whistle to keep their spirits up while the impatience of their public mounts.

The former foreign secretary Douglas Hurd, hardly anyone's idea of a boat-rocker, said yesterday the UK was not getting a fair crack of the decision-making whip, that the US - and specifically the military - is calling the shots, and suggested that in doing so it is getting much of it wrong. So how should the Prime Minister use such influence as he has when he meets George Bush this week?

The first thing he should say is that they must come up with a proper plan for Iraq, for the sake of Iraq, world security, and their own and their countries' futures. This may seem naive, but so far Bush and Blair have not come up with a coherent strategy for Iraq, an impression that they can envisage a coherent and practical end state, or how it might be achieved.

We have had rhetoric and grandstanding by the bucketful and much talk of democracy defeating terrorism, but of a carefully planned stratagem for Iraq with a clear mission, lines of operation and tactical means of achieving it, we have had little.

Second, the Americans must stop personalising this struggle, which only serves to polarise it. This weekend Iraq is in national revolt, but Donald Rumsfeld has characterised the violence as being confined to "isolated pockets". The radical cleric Muqtada al-Sadr has been depicted by British and American staff of the Coalition Authority as "marginal", yet Sadr is becoming the emblem of a pan-Iraq revolt. He is the youngest son of Sadiq al-Sadr, most revered of the great Shia martyrs murdered by Saddam hitmen in 1999; the Shia suburb of the capital has been renamed Sadr City after him. The powerful clerical Sadr clan has tentacles reaching into Iran and Lebanon.

Centring the conflict on him looks like victimisation by a superpower and creates a potential martyr in Arab minds. "Going for what the Americans love to call a 'high value target' like Muqtada is a huge mistake," a senior British security adviser told me last week. Singling out Muqtada al-Sadr evokes ominous parallels with the targeting of the Mogadishu warlord Mohamed Farrah Aideed by US forces in Somalia: 18 US troops were killed and Aideed died years later of cancer, a free man.

In this kind of urban jungle warfare, high-technology weapons such a laser-guided bombs and Apache gunships are diminishing assets. The advantage lies with the guerrilla who knows his terrain fighting with improvised bombs, rocket grenades, and shoulder-launched anti-aircraft rockets. Main battle tanks can become traps for their crews, as happened in Grozny, as they get caught in narrow alleys prey to Molotov cocktails and hit-and-run snipers. Knock down a mosque and the rubble becomes a natural rampart for the defenders.

Would sending more troops help? It might, but probably only in the short term. Besides, if the country-wide revolt continues from Kut to Kirkuk and Karbala, Nasiriyah, Najaf, Fallujah, Amara, Basra and Baghdad as the main flashpoints, the US and UK would have to put in an extra 100,000 soldiers at least. This is the calculation made by Major Charles Heyman, leading ground operations analyst of the Jane's Defence Group. "Resources aren't very deep, and America does not have many troops to spare."

America and Britain are likely to boost troop numbers by freezing the garrison "rotations" already under way. In Baghdad the 1st US Cavalry Division is due to take over from the 1st Armoured Division, which has now been told to stay on until further notice. In Basra, and Amara in the south, the 1st UK Mechanised Infantry Brigade is due to take over this week from the 20th Armoured Brigade, which will now be told to stay on.

Tony Blair should remind George Bush and Donald Rumsfeld that increasing forces can only be a stopgap, to hold the line by offering security and protection for the coalition forces themselves and keep the lines of communication open along the main arteries to Jordan and Kuwait. Use them for anything more - for taking out the high-value targets favoured by Paul Bremer and Rumsfeld - and America and its partners will be heading for their "Somalia moment" sooner rather than later.

Faced with the prospect of a growing urban guerrilla campaign, Blair and Bush will have to rethink the politics. They must initiate a more practical stabilisation programme, involving Iraqis from all quarters, possibly including the Shia militias. They will have to remedy the single biggest errors of the American authorities and of Bremer himself. The first was to disband the 400,000-strong Baathist Iraqi army. That Iraqi police and military forces were then reconstituted was too little and too late, according to British and American critics now serving in Baghdad.

Fatally, as it now appears, Bremer refused to hand over the military training programme to General John Abizaid of Central Command, an Arabic-speaking expert on the region. Funding for arms and equipment has been held up by Bremer's office, according to one senior UK officer. Last year Bremer tried to cut the salaries of Iraqi police being trained at the highly successful police academy improvised by British forces in Basra.

It is not as if the Americans have been short of good advice from the most skilled and experienced diplomats and soldiers on the spot. An extremely well-placed source tells me that "90 per cent of the American and British military are against going for high-profile targets and would prefer a softly, softly approach". But Bremer does not listen. He has ignored General Abizaid, and Britain's Sir Jeremy Greenstock, who is said to be quitting Baghdad early in frustration.

Blair should emphasise the glaring cultural differences and disagreements between the British and Americans over peacekeeping. The British have had an easier area to control in the south east, though Amara, where Saddam armed tribal militias, has an alarming capacity for spontaneous combustion. But in Basra the British have succeeded with a tried- and-tested, carrot-and-stick method: riot control and wheeler-dealing.

A solidsecurity deal, involving as many local forces as possible, will be vital for the handover to Iraqi national authority on 30 June to have any credibility. Otherwise, the roads as well as the cities will become more vulnerable, and hostage-taking and kidnap will become hard to contain.

If 30 June means a continuation of a largely American-nominated authority with little local support and an increasingly desperate coalition force to back it, this will not only signal the beginning of the end for America and its allies. It could mean the end of the end for the great neo-conservative experiment in Iraq. Complete withdrawal might also then be the end of the end for the political careers of Bush and Blair. They both really need this to work.