The first episode in the series meets the vets and handlers looking after the 1000 dogs and 500 horses that serve with the British military.

Many have come from backgrounds a world away from the military such as entering Britain's Got Talent with their dogs, hairdressing and fitting car windscreens. The documentary tracks their training alongside that of the animals in their charge, providing an insight into how they form bonds with these incredible creatures.

The third and final episode of the series follows a private and her dog on patrol in Afghanistan, a corporal and his Labrador as they search for explosives and one soldier and her dog as they come under fire from insurgents whilst on patrol on the front line with their unit.

Animal Heroes also catches up with the trainees at the Defence Animal Centre as their course draws to an intense and challenging close. They are put through their paces as they go on exercise with all their kit and their dogs for the first time and are then put under pressure in a simulated prison riot exercise.

Plus they face their toughest challenge yet when they are dragged from sleep in the middle of the night and asked to use their dog to help interrogate a suspect – this is against every rule in the book, but will the trainees buckle under the pressure?