LONDON A gun used in the assassination of Archduke Franz Ferdinand in Sarajevo on June 28, 1914 - the incident that set in train events which led to the First World War - will be unveiled on Sept 25 at the Imperial War Museum.

The gun and a homemade grenade, on display for the first time in the UK, were part of the evidence gathered by police after they were used by a small group of Serbian nationalists who wanted to attract attention to their cause.

The consequences of the bullets fired from the small black pistol by a sickly teenager would cost the lives not just of Franz Ferdinand and his wife but of millions of people across Europe, scar the lives of millions more, and sow the seeds of WWII.

The exhibition, marking the 90th anniversary of the Armistice, ends with the ominous words of the French Marshal Foch after the Treaty of Versailles “This is not peace, it is an armistice for 20 years.”

“If there is a moral in our story, it is that a relatively minor event within weeks brought about the first truly total war, the first war in history genuinely to overwhelm the world,” curator Terry Charman said.

As the exhibition was being completed he showed the US defence secretary, Robert Gates, around on a private visit. Struck by the conviction of the British soldiers - and some of their leaders - that they would be “home before Christmas,” Gates said “We said the same about Iraq.”

The exhibition - which includes a letter on the brink of war from the British prime minister, Herbert Asquith - focuses on the lives of 90 individuals, including Winston Churchill and Lloyd George, and features the mess-tin and spoon of future American president Harry Truman and poignant personal possessions of ordinary people.

The gun and bomb are a rare loan from the Heeresgeschichtliches Museum in Vienna. They were collected by police after the archduke was killed by Gavrilo Princip, an 18-year-old Bosnian Serb.

One reason for mounting the exhibition now, Charman said, is that of the five million people who enlisted in the British forces in the war, just three remain alive Bill Stone, Harry Patch, and Henry Allingham.

“Despite the enormous loss of life, and the promise never to forget the fallen, it is now completely overshadowed by the Second World War,” he said. “We need to remind people.”—Dawn/Guardian News Service