On arrival at Camp Bastion, the main logistics base for the military in Helmand, Royal Engineer squaddies in 59 Independent Commando Squadron, attached to 28 Regiment, undergo confidence training on the demolition range.
Driving through the desert to the range located minutes from the main gates of the base, the soldiers don body armour and helmets, not just because of the risk of attack, but because of the plastic explosives they are about to experiment with.
PE4 is carried by every member of 59. On the range, squaddies mould the plastic explosive into a lump the size of a cricket ball round a line of detonation cord. A detonator is taped to the cord and a safety fuse attached. Once a grip switch is fitted to the end it is fired. The safety fuse burns to the detonator that fires the detonation cord, which, burning at 6km/s, releases energy from the PE4 creating a small explosion.
The purpose of the exercise is to make the soldiers feel comfortable handling the explosives, as next time they could be doing it under fire.
After a second practise run the soldiers move on to something bigger. The 'mousehole' charge is four cricket balls of explosive, one taped to each corner of a cross of wood. In the event that the troops have to move into a hostile building it is undesirable to rush through the door and risk getting shot. Instead they blow a hole through the wall.
All four balls of explosive are set up using the same method used for the small practise explosions, but are connected to a single safety fuse and click switch. The mousehole charge is placed against the wall by two soldiers while two others scout for insurgents. Once lit the four take cover - on the demolition range that is behind an earth bund some 20m from the explosion.
The overpressure rips through the soldiers' bodies as they lie with their fingers in their ears and their mouths open to stop their eardrums exploding. As soon as it passes the soldiers are on their feet and charging through the hole they have created in the wall. This time it is just to put out burning rags, but in the field they might be met by Taliban rebels.