This biographical article is based on research in the Scottish Record Office and in the volumes of the Notable British Trials series. Oscar Slater liked to describe himself as “the Scottish Dreyfus”, but Leslie Blake points out that it is more accurate to describe Detective Lieutenant Trench, who ruined his career by his determination to see Slater’s conviction for murder re-investigated, as the “Scottish Colonel Picquart”. Unfortunately, Trench (who died in 1919) did not live to see the quashing of Slater’s conviction by the newly-established appeal court in 1929.