Mr Briggs' Hat, By Kate Colquhoun

"A Sensational Account of Britain's First Railway Murder," declares the cover in the manner of a 19th-century penny dreadful. In fact, this book, stemming from the bludgeoning of respectable banker Thomas Briggs in a closed compartment on the evening of 9 July 1864, is anything but sensational. Kate Colquhoun's irreproachable unpicking of the case is meticulous, patient, thorough and measured. A real-life police procedural of the highest order, it provides a picture of Victorian society as vivid and detailed as WP Frith's painting of Paddington Station in 1862.

Yet the case was sensational. The first murder on Britain's new railway system was made more shocking since it took place in a first-class carriage. Public interest was galvanised when Detective Inspector Richard Tanner pursued the putative killer's boat across the Atlantic. New York was also swept up by the arrest of German tailor Francis Muller, who had the misfortune to arrive after his pursuers. When Muller's humble effects turned out to include damning circumstantial evidence in the form of Briggs's gold watch chain and silk top hat, the accusation of cab driver Jonathan Matthews appeared justified.

"Muller the murderer," crowed the British press in a manner familiar from our own time. Yet there were doubts from the start. "It is a strange story," declared The Times, "but the strangest part is the disproportion of the audacious enormity of the crime and the feebleness of the attempt to escape its consequences." When the case came to court, the evidence turned out to be less conclusive than first appeared. Defence counsel produced similar toppers, bought on the second-hand market. Muller claimed he bought the chain on the docks before leaving London. No murder weapon was ever found. The cabbie Matthews proved in desperate need of the £300 reward, while an unshakable witness insisted that he had seen two men in the train compartment, both unlike Muller, with Briggs.

Colquhoun brilliantly elucidates every aspect of this distant shocker, from sweatshops (20,000 stitches required for every shirt) to London's 700 pawnshops (5,000 pledges a month). A cab drive across London is described with a vividness that surpasses anything in Sherlock Holmes. But the figure indelibly imprinted on the reader's mind is Muller. We can see him in the Old Bailey dock: tiny, dignified, moved to tears by the smallest acts of kindness, polite even when condemned.