This film appalled me. It's about a three-man American bomb disposal unit in Iraq. I spent 15 years engaged in similar activities with the British Army (including a stint as one of the principal staff officers for bomb disposal in southern Iraq). The opening sequence seemed accurate and well-observed: an officer, played by Guy Pearce, sends a robot – also known as a "wheelbarrow" – to dispose of a device. But the film then descends into numerous glaring inaccuracies.

After Pearce's demise, a new operator comes in: Staff Sergeant William James, played by Jeremy Renner. This man is basically insane. He's supposed to have dealt with some 870 devices, which is completely unbelievable – it would mean dealing with three improvised explosive devices a day – and he just rocks up near a device and puts on a bomb suit. There's none of the usual military procedure: no planned operation, no isolation, no robots. At one point he is shown pulling five or six 155mm rounds out of the ground; each of those weighs 44kg, and he's wearing a 40-50kg bomb suit as well. The fundamental stupidity is just staggering.

If a bomb disposal officer started behaving like this, he or she would be shipped home in minutes. James makes us look like hot-headed, irrational adrenaline junkies with no self-discipline. It's immensely disrespectful to the many officers who have lost their lives.

The film does succeed in showing that on a tour of duty, there is no overarching story – it's just a series of incidents. And when James gets home, he has trouble adjusting to the triviality of everyday life, which is realistic. A few days before, you've been dealing with stockpiles of munitions, or an improvised explosive device, and now your wife is asking you to choose between 47 different types of cornflakes. You do think: "Crikey."

• Guy Marot is a former bomb disposal officer with the Royal Engineers. The Hurt Locker is on general release.