Cycling journalist Ned Boulting’s latest book, 1923, is the story of how the purchase of the fragment of a newsreel report about a century-ago edition of the Tour de France led to an obsession with the forgotten rider seen on the film crossing a spectacular bridge. But this is far more than just another cycling book. It tells the story of a Europe still riven by tension and hatred five years after the Armistice.

The story begins when a friend pointed him to an item for sale in an online auction:

Ned bought the film for £120, and began a fascinating journey (literally and metaphorically) of discovery. The question mark over the date in the auction house listing was appropriate. The film, just over two minutes long, actually featured the 1923 Tour de France. Boulting found that the early Tours after the Great War followed exactly the same route, so he resorted to reading old newspaper articles, and even searching for weather reports, to establish that the stage from Brest to Les Sables d’Olonne featured in the film took place on 30 June 1923.

That £120 purchase could have had disastrous consequences. The company that made Boulting a digital video out of the ancient reel told him that the original was a nitrate film, and so highly flammable. Ned didn’t admit to the film restorers that the item had sat next to the radiator of his house after popping through his letterbox after he won the auction. If you happen to have a very old film reel at home, do check that it isn’t nitrate…

This is one of the defining images from the 1923 story. It shows the hero of the book, Théophile Beeckman, racing ahead on the bridge across the river Vilaine at La Roche-Bernard. As the subtitle of the book, The Mystery of Lot 212 and a Tour de France Obsession, suggests, Boulting became obsessed with uncovering the story of Beeckman, a man so obscure that he has all but vanished from the records. (As Ned discovered, there was virtually nothing about the rider online until he published 1923.)