ITV's Long Lost Family special delves into search for soldiers missing since First World War

In fields across the world lay the bodies of hundreds of thousands of fallen British servicemen, yet to be identified.

-> How army of people helped Leeds remember war that changed the worldThis one-off episode, Long Lost Family Special: The Unknown Soldiers, hosted by Davina McCall and Nicky Campbell, features "unprecedented access" to the Ministry of Defence’s War Detectives, an elite team who use forensics and ground-breaking technology to identify the bodies of unknown British and Commonwealth Soldiers.

There are over half a million World War service personnel with no known grave and these historical investigators are tasked with identifying those whose remains are found and trying to trace their surviving families.

Each year around 60 bodies of British service personnel killed in battle are found by farmers, builders and archaeologists worldwide.

Davina McCall said: “Every investigation that the War Detectives take on starts as just a case number, the anonymous remains of a soldier. The detectives’ mission is to identify that soldier.”

The presenters join the detectives as they consult war maps, diaries, medical and service records and use DNA testing to piece together the life of each soldier from the time they left British shores to their final steps on the battlefield. They meet the families of the missing, helping them form a fully-rounded picture of their long-lost relative and finally laying them to rest at a full military burial.

-> How Wakefield women helped First World War effort on home front and abroadAlong the way they are able, though sometimes unable, to confirm to descendants whether remains discovered are those of their relatives who served in the war.

They also attend the military funerals given to those whose bodies are discovered decades on from their deaths.

In one case, more than 100 years since the First World War, Colin, his wife Carol, daughter Lara, soldier grandson Ricky and his wife Rosie follow the journey of ancestor Private Frederick Foskett took at the outbreak of World War One and travel to Belgium for his burial.

War Detective Louise Dorr said: “It’s been definitely worth opening Case 272 again. If ever there’s a chance that we can give these men back their names it’s worth it. I just can’t imagine the horror that Frederick’s parents must have gone through, never knowing when they went to their own graves what had happened to their boy. And today at least we’ve managed to put some of that to rest.”

-> The story of Britain’s fishermen and the crucial yet often undervalued role they played during the First World WarThe special, produced by Wall to Wall, airs on ITV tonight between 9pm and 10.20pm.