From the German side a young soldier began to sing a song from his homeland. “He can certainly sing!� observed one British soldier to his colleagues. One by one other German voices joined in until a Saxon chorus rang out through the fields.

After a silence some soldiers from Kent, England began to sing the Christmas carol “God Rest Ye Merry Gentlemen.� Other voices joined, and when they finished there was applause from the German trenches.

Then the most remarkable thing happened.

From the German trenches a strong voice sang “Stille Nacht.� This song was instantly recognisable to the British troops as “Silent Night.� This time all the soldiers, German and British alike, united in two different languages to celebrate the birth of Christ.

“Someone’s coming!â€? shouted a forward sentry. Through the darkness all eyes were fixed on a lone German soldier holding a white flag. He stood in the middle, between the German and British trenches, an area called ‘No Man’s Land’, and greeted the British troops.

One by one soldiers on both sides cautiously climbed from their trenches and made their way to No Man’s Land. They chatted, shared cigarettes and brandy and showed each other photos of their families back home. Some soldiers buried their dead colleagues whose bodies had, until now, been impossible to bury. Some soldiers swapped addresses.

This remarkable unofficial truce, this spontaneous manifestation of humanity, spread along a large part of the 500-mile Western Front where more than one million men lay in mud with instructions to kill each other.

Alfred Anderson was eighteen at the time. He is the last surviving witness of that Christmas of 1914. He remembers how the truce lasted until the afternoon of St Stephen’s Day, the day after Christmas. Tears well up in his eyes as he remembers.

“It was such a short peace,� he says, “in such a terrible war.�