Sir James Dale Cassels (22 March 1877 – 7 February 1972) was a British judge, journalist and Conservative politician.
He was the only son of Robert Cassels, assistant clerk at the Bow Street Magistrates' Court. He was educated at the United Westminster City School where he learnt shorthand.
He began work as a reporter with the Sussex Coast Mercury in Worthing, subsequently moving to London, where he worked for the Chelsea News and the Fulham Chronicle. In 1898 he joined the staff of the Morning Post. He stayed with the paper for fourteen years, originally as a parliamentary correspondent, later becoming a sub-editor.
In 1908 Cassels was called to the bar at the Middle Temple. He practised on the South-Eastern Circuit, and his heavy caseload led to him abandoning journalism in 1911. His legal career was interrupted from 1916 to 1919 by the First World War. Cassels served on the Western Front, fighting at the Battle of Arras and was twice mentioned in dispatches. He reached the rank of captain, and chaired a number of courts martial. In 1923 he took silk, appearing in the criminal courts and in the King's Bench Division of the High Court. He was leading counsel for the defence in the celebrated murder trial of Sidney Harry Fox, but was unable to secure an acquittal. His manner was brusque, and he was highly amused to be told that he was considered " the second rudest man at the Bar", Sir Patrick Hastings being the rudest.
In 1927 he was made recorder of Guildford and in 1928 recorder of Brighton. He was also chairman of East Sussex Quarter Sessions. In 1939 he was appointed as a judge, and received a knighthood. He presided over a number of notable trials in the 1950s before retiring in 1960. He served as a special Commissioner of Assize at Norwich in 1961 and at the Central Criminal Court in 1962, clearing a backlog of cases.