IT IS THE DESPERATE CALL FOR HELP THAT HAS ECHOED ACROSS BATTLEFIELDS THROUGH THE AGES.

'MEDIC! WE NEED A MEDIC OVER HERE! NOW!'

Doctors, nurses, medics and stretcher bearers go where the bullets are thickest, through bomb alleys and mine fields, ducking mortars and rockets, wherever someone is injured and the cry for assistance goes up. Their job is the put themselves in the heart of danger - to run into battle to rescue the wounded and to risk their own lives as they try to save the dying.

War at its rawest is their domain, an ugly place of shattered bodies, severed limbs and death. Theirs is the most selfless of acts. They fulfil society's vital pledge to its warriors that they will not be abandoned on the battlefield. Yet, more often than not, what they do goes unnoticed - except by those who are still alive only because of the extraordinary courage and skill of their rescuers.

This is the story of those brave men - and, increasingly in this day and age, women - who go to war armed with bandages not bombs, scalpels not swords, and put saving life above taking life. Many have died in the process, the ultimate sacrifice for others to ensure that when the cry of 'Medic!' is heard, it will be answered. Regardless of the cost.

From the beaches of Dunkirk to the desert towns of Afghanistan, there can be no nobler cause.