Rent The Last Chance (1937)

Alan Burmister (Frank Leighton) leaves Devon on a secret gun-running expedition immediately after his engagement to Mary Perrin (Judy Kelly) is announced; he returns at Christmas to find himself accused of the murder of Ivor Connel (Alfred Wellesley), a moneylender. Mary's father had always hoped that his daughter would marry John Worrall (Wyndham Goldie), a rising barrister. Worrall is briefed for the defence, but when he loses the case and Alan is condemned to penal servitude for life, no one but the judge realises that he has not made use of the best piece of defence evidence...