Youngsters at an Argyll and Bute school have uncovered a remarkable First World War tragedy involving one of its former pupils.

The Dunoon Grammar School pupils unearthed the story about Walter Sinclair Smith while carrying out research for a Remembrance Day project.

Now they are working on a short film depicting what they have discovered, which will be shown to the entire school in the run-up to Remembrance Day.

Councillor Bruce Marshall, chair of the Bute and Cowal area committee, said: “What these young people have discovered is a very valuable addition to our local history.

“It’s incredible to be able to place this young local man at this key juncture in the war. Finding out more about him and his family has been extremely important in helping pupils understand that the young men who went off to fight these wars were just like them, yet had to endure hardships which young people nowdays would find difficult to comprehend.

“I congratulate all those involved in this project, and look forward to seeing the film once it has been completed.”

For decades, Dunoon Grammar School pupils have passed by brass plaques listing the names of former pupils and staff who fell during the world wars. Earlier this term, a group of pupils decided to choose a name from the list and find out what they could about that person.

They were drawn to the name of Walter Smith, largely because he shared his name with the former Scotland football manager. On researching his role in the Great War, the extraordinary yet shattering story of how he died was revealed.

Serving with the 5th Cameronians Scottish Rifles, Walter was stationed in the trenches of the Western Front near Armentieres, Northern France during Christmas, 1914.

His unit was one that participated in the spontaneous and unofficial ‘Christmas truce’, exchanging gifts, stories and pictures of loved ones with the Saxon unit of the German army they faced across the battlefield. Several games of football between the opposing armies also took place.

The Christmas truce is regarded by many as being the iconic moment of peace and humanity during one of history’s most brutal and bloody wars, and has inspired a range of books, movies and songs.

Late in the afternoon of Christmas Day 1914, while British and German soldiers were mingling on no man’s land, a shot rang out from the British lines, accidentally fired by a regular from the Scottish Rifles. A German sniper immediately replied, but instead of firing on where the shot had come from, he fired at the first British soldier he saw and shot him through the head.

That soldier was Walter Sinclair Smith. He died without regaining consciousness on Boxing Day.

Walter was buried by his comrades in a quiet area behind the lines. His grave was marked by a simple wooden cross with a small evergreen tree planted behind it. It is unknown if any of his three brothers, who were serving in the same battalion at the time, witnessed his death or attended his funeral and burial.

This tragedy appears to have brought the temporary truce and period of ceasefire to an end on that part of the front line. The Saxons later apologised - the bullet had not been fired by anyone in their unit but had instead come from a neighbouring Prussian unit.

Dunoon Grammar pupil Sean McMahon, who plays the part of Walter in the school production, said: “Walter was one of five brothers, four of whom were involved in the Great War.

“We have tried to get across that Walter and other ex-pupils like him are more than just names engraved on a brass plaque, but real people who found themselves in the most terrible of events. It was amazing that Walter took part in the iconic Christmas truce of 1914, but heartbreaking how he was shot on Christmas Day itself.”

The video produced by the pupils will include actual pictures of Walter Sinclair Smith and his brothers as young children and in the trenches on the Western Front. The school has also unearthed images of Walter’s original grave taken on 26 December 1914.

Dunoon Grammar School pupils have tried various routes to track down any of Walter's living relatives, including putting an advertisement in the local paper, but have so far drawn a blank.

Head teacher Stewart Shaw said: “I am very proud of the work of our young people in uncovering and retelling the story of our former pupil.

“The story of Walter Sinclair Smith is remarkable and tragic in equal measure. It is important as a school community that we do all we can to remember former pupils and staff who have fallen during conflict. Each name listed will have a similar story to Walter’s and their sacrifice will never be forgotten.

“We are still hopeful that someone might come forward who is related to Walter in some way. It would be wonderful to have any living relatives with us as guests of honour when we give the film its first showing.”