 The trial is covered in Rebecca West's "The Meaning of Treason".The depositions in his trial are held at the National Archives under reference CRIM 1/484 and his pardon is held under reference CRIM 1/585/142.The Home Office and Security Service files on him are held by The National Archives under references HO 45/25805 and KV 2/254 1939 Nov 01-1946 Jul 20 respectively.