The snaking convoy of soldiers and tanks passed down the main highway south towards Basra, past an old cola factory, and past a junction they call Danny Boy - scene of a bloody battle in the past few weeks, when British bayonets were fixed as the soldiers launched an infantry assault across the marshland.
A little further, and this bandit country dishes out its traditional welcome: a volley of Kalashnikov bullets. But we keep moving. The fingers of the Black Watch soldiers twitch by their triggers as the men scan the bushes for an ambush.
Perched on the back of an open-top Land-Rover, I was with soldiers of the Black Watch just a few days ago as they returned south to their base near Basra, ready for their next assignment. They knew then that their tour had been extended past Christmas, but not what we now know: their most likely deployment is up north, to operate directly under US command.
Most were depressed that they would be staying longer in this "awful place" but, if they are to stay, the men would probably be happy to operate alongside the Americans. If nothing else, they can test their mettle against the Yanks.
Not that they will be leaving behind any kind of quiet zone. Since their arrival in July, many Black Watch soldiers have seen fierce fighting against the Mahdi army in both Basra and the city of al-Amarah, further north. With a truce agreed, things have quietened down a little, but am-bushes are still common.
For the men of the Black Watch, the highlight of our journey south was a head-on crash between two Iraqi cars, one of which was trying to bypass the convoy. "Did you see that? What a peach!" said one soldier. These men have mixed attitudes to combat: they admit to fears about staying alive and say that they long to be back home, but they regale you, too, with stories of "contacts" with the enemy, and "body counts" of militiamen they have taken out during their tour. They would be keen to go somewhere "less boring".
Their officers may take a different view. Many regard the US attack on Najaf as a brilliant success: fighting the Mahdi army to within ten yards of the Imam Ali Mosque, without causing any damage to the shrine, "was a great feat of arms", said one. However, some say that the US is bungling the fight against the resistance, mainly because of its failure to tackle the non-military aspects of winning the peace: providing jobs, for example.
These differences will be brought to the fore if the Black Watch deploys to the combat zone south of Baghdad. It includes the towns of Latifiyah, Iskandariyah and Mahmudiyah, all notorious for their roadside bombs and kidnappings. For the past fortnight, US marines have been sweeping through these areas trying to make them secure, but, thinly stretched, they have moved little beyond "reconnaissance by fire" tactics. These, in a nutshell, involve driving through a hostile area, hoping to draw fire, and then, with an AK-47, eliminating anyone who pops their head out. "If we get one round of incoming fire," a colleague was told, "we will put down 3,000 before we even dismount from our vehicles. So you better take cover!"
It boils down to a strategy of attrition that is, on its own, ineffective. Robust local security forces have to hold the towns when US (or British) columns have moved through. Yet there is little sign the Iraqi security forces are anywhere near ready. Those police who dare to remain in Latifiyah side with the insurgents.
Britain has made no secret of its criticism of the US strategies, but don't believe the talk of a bigger British say in decisions. As one UK military officer in Baghdad said: "It's a veneer. This remains an American show." Geoff Hoon's "good ally" will have to run a fool's errand.