When archaeologists uncovered the tip of a British steel helmet hidden beneath a Belgian field, they barely expected to find the almost complete corpses of two fallen soldiers - let alone rare artefacts which would bring them tantalisingly close to identify the men.

Many of the lost were killed by high explosive shells

The soldiers' remains were the 123rd and 124th bodies found by Belgian experts excavating the ground beneath a new industrial estate at Boezinge, north of the town of Ypres.

Unknown to the developers the site was being built right across the British and German front lines and the infamous No Mans' Land in between the opposing trenches.

As work began, the ground gave up a wealth of personal items, including a French dictionary and a jar of Bovril, along with the bones of British, French and German troops.

Following the dig

As archaeologists' trowels replaced the developers' mechanical diggers, I took a TV crew from BBC Two's Meet The Ancestors series to follow the excavation.

The remains of hundreds of unknown soldiers have been found

Filming the reactions of experts as they removed the earth from bodies 123 and 124, it became clear they were fascinated to see remains in such good condition.

Few intact skeletons are found on this WWI battlefield, since the majority of the dead on both sides at Ypres were quite literally blown to pieces by artillery fire.

However, not only were these bodies virtually intact, but these men died in their boots, surrounded by their military kit and private belongings.

A tiny glass iodine ampoule, pens and a wooden brush all survived from their personal effects. A small leather purse - containing French coins dated 1917 - had also endured the muddy grave.

Survived the mud

Only one British soldier has been identified from his remains in this area in the past quarter of a century, but it seemed as though the sheer number of artefacts around these two bodies might lead us to their names.

Soldiers often scratched their service numbers or a name on to personal items, but an examination of both a dessert spoon and the wooden brush revealed nothing.

Metal regimental badges did identify the pair as soldiers serving with the Royal Welch Fusiliers.

One corpse wore a metal ID tag

Military historian Paul Reed, accompanying the diggers, confirmed this regiment served at Boezinge from the end of 1916 to 31 July 1917 - the start of the battle of Passchendaele, where more than 300,000 British soldiers were to lose their lives.

Four hours into the painstaking dig, the team found something that would surely point them to the men's names - one corpse wore a metal identification or "dog" tag.

The compressed-card tags issued to every soldier disintegrated after a couple of years buried in the Flanders mud - the main reason why so many of the corpses uncovered in the area are re-interred beneath gravestones dedicated to "A soldier known to God".

More robust metal ID tags were extremely rare during World War I and had to be paid for by the soldiers themselves.

Dog tag

Our disc was sent to the UK Ministry of Defence, but the metal proved too corroded to surrender the name of the man who had bought it more than 85 years ago.

Though he might not have discovered their names, Paul Reed thinks he can explain how the men might have died.

A gas mask gives clues to the men's final moment

The tube of a gas mask was found leading to the mouth of one soldier, indicating that the pair died during a poison gas attack.

It is likely the two fusiliers were manning a forward observation post when they were killed by German shrapnel and then buried by the earth thrown up in the explosion.

Their bodies remained beneath this Flanders field for more than eight decades.

And though the battlefield clings to their identities, later this year these two unknown soldiers will be laid to rest, this time in a military cemetery.

The Forgotten Battlefield will be screened on BBC Two at 2100 GMT on Wednesday 6 March.