A British soldier refuels his Challenger II near Basra
At £5.6m a piece, the UK's main battle tank, the Challenger 2, is an expensive piece of kit but, as BBC News Online discovered, it is not a great environment to work in, especially in the stifling heat of the Iraqi desert.
War is never an easy business, but for the crews of the British Challenger 2 tanks in action in Iraq this is an especially hard campaign.
The British Army has 40 of these 61-ton behemoths, many of which are in the front line near Basra.
They replaced their predecessors, the Challenger 1, in 1994.
The new model has 150 improvements over its predecessor, which saw action in the first Gulf War in 1991.
Challenger 2 has a crew of four:
The commander (who may be anything from a lieutenant to a corporal): it is his job to liaise with his superiors, pass down orders and manage the tank and his men.
The operator/loader (usually a corporal): his job includes manning the radio, loading ammunition for the main gun and the machine gun, and cooking for the crew.
The driver (usually a trooper): who steers the tank, keeps watch through his periscope and maintains the engine.
The gunner (also either an NCO or a trooper): who controls the direction and angle of the 360 degree turret and fires the main 120mm gun.
Francis Tusa, editor of Defence Review, said one important improvement on the Challenger 1 was the fact that the commander now had a "hunter/killer nightsight".
This meant that, as the gunner was firing at one target, the commander could be searching for the next target.
Each man will be trained sufficiently to do each other's jobs but they will tend to specialise in their own areas.
The crew will eat, sleep and work together for hours at a time and former Challenger crewman and Gulf war veteran Alistair Miller, from Belfast, told BBC News Online: "There is a tight bond between the crew.
"We were like brothers but the commander is like the daddy."
He said the banter between the crew could be "brutal" at times but would never get out of hand.
Inside the tank compartment it is stiflingly hot during the day but often very cold at night.
A British soldier takes a break under his Challenger II
Mr Tusa said the Challenger 2 had an environmental control system which was an improvement on Challenger 1 but he said it was unable to cope with the sweltering heat of the desert.
Mr Miller said another morale-sapping factor was the darkness.
"It was always very dark, with all lights painted red to prevent the tank being noticed at night. You are forever banging your head or elbow or scraping your knuckles."
The tank is also "extremely cramped" with four fully grown men sharing a space barely 15 feet by 10 feet and only about six feet high.
Inside this space the men have to stow four NBC suits each plus rations, equipment and clothes.
The crew compartment has an air filtering system, as well as a heating and cooling system, and is separated from ammunition for obvious safety reasons.
Mr Miller said the overriding smell was of burning cordite, from the rounds which were being fired.
Mr Tusa said that although the tank was designed to be driven while completely sealed, most commanders preferred to drive "hatch up" so they could poke their heads out and check out their landscape unfettered by periscopes or night sights.