Talk to Iran. Now.

Maps are nice, aren't they? So let's have a look at a few maps of Iraq. This one shows Iraq's administrative divisions, its roads and its rivers. Note especially that there are essentially two major roads between Baghdad and Basra. One runs along the Tigris valley parallel to the Iranian border. The other runs just inside the Euphrates valley on the right bank of the river, crossing it twenty or so miles upstream of Nasiriyah. There are two secondary roads, one of which runs up the left, western bank of the Euphrates from a junction with the main road before the crossing as far as Karbala, the other of which connects the Nasiriyah bridges with Kut on the northern main road. The first of these, Highway 8, is known to the Coalition as Main Supply Route Tampa, the road which connects the US Army's Logistic Support Area Anaconda at Balad South-East airfield north of Baghdad, Baghdad Airport, Mosul, Basra and Kuwait City. Literally everything the coalition uses comes in either up this road from the docks in Kuwait, or else into one of the three strategic air bridgeheads (Baghdad, Balad, and the RAF's Basra Air Station) and then along it to the point of use.

This map shows Iraq's major oil infrastructure. You will note two things - first, the core-centric nature of the refinery at Baiji, which is why the insurgents go to such lengths to harass it, and secondly that the only pipeline between northern and southern Iraq runs next to Highway 8.

This map shows the distribution of religions and tribes in Iraq. Notice that the entire area of the main roads, pipelines and rivers (not to speak of the main railway line between Basra and Baghdad) is shown as entirely Shia, and borders on Iran. It's also, although it's not on the map, heavily SCIRI.

This map shows Iraq by population density. Note that, among many other things this map should tell you, the top 3 cities make up one-third of the population. The only areas of Iraq that can be described as "quiet", except for Kurdistan, are the ones where there is either nobody to fight or nothing to fight over. The much mocked Information Minister, Mohamed Ali Al-Sahaf, had a point when he described the US army advancing on Baghdad as being like a snake in the desert - the only serious fighting before Baghdad occurred at the urban choke points of Nasiriyah and the Karbala area.

Now, there are some 5 coalition divisions in Iraq. There is the British-led division in the south-east, more and more these days concentrated around Basra. There are two US divisions in Baghdad, another division equivalent split between the north-central zone and the Karbala/Najaf area, and one brigade up north. There are also the leftovers of the old Multinational Division South Centre, not that they add up to much. To put it another way, there is a yawning gap between the British in Basra and the road to Kuwait, and the bulk of coalition forces around Baghdad. It is open to the Sadrists, SCIRI or Iran to make a retreat from Iraq very difficult and very bloody.

There is no alternative line of retreat. The road towards Jordan leads through Fallujah and Ramadi, and even the Jordanians might not be happy to help us make our exit via..Israel. Going north is a nonstarter - it means marching through Baghdad and the Sunni insurgent heartland, and then bringing the army over the mountains into Turkey. (Look at the first map, which shows precisely one tarmacked road crossing the border.) The light brigade up in Kurdistan could leave that way, or by air, but the three armoured divisions can't. They have to go south, back the way they came. The conclusion?

We need to open military-to-military talks, so-called staff conversations, with the Iranians. We need to discuss the modalities, in the Northern Irish phrase, of an orderly departure. We need guarantees that their supporters in Iraq will not blow the bridges as they did in the first Shia rising, in April, 2004, and won't mortar the airfields.

And this map is a work of psychotic stupidity.