Captain Frederic John Walker, (3 June 1896 – 9 July 1944) (his first name is given as Frederick in the Oxford Dictionary of National Biography and some London Gazette entries) was a Royal Navy officer noted for his exploits during the Second World War. Walker was the most successful anti-submarine warfare commander during the Battle of the Atlantic and was known more popularly as Johnnie Walker (for the Johnnie Walker brand of whisky). Early life and career Walker was born in Plymouth, the son of Frederic Murray and Lucy Selina (née Scriven) Walker. He joined the Royal Navy as a cadet in 1909 and was educated at the Royal Naval Colleges at Osborne and Dartmouth, where he excelled. First serving on the battleship as a midshipman, Walker as a sub-lieutenant went on to join the destroyers and in 1916 and 1917 respectively. Following the end of the First World War, Walker joined the battleship . He married Jessica Eileen Ryder Stobart, with whom he had three sons and a daughter. Interwar period, 1920s–1930s During the interwar period Walker entered the field of anti-submarine warfare. He took a course at the newly founded anti-submarine warfare training school of HMS Osprey, on the Isle of Portland, which was established in 1924. Walker consequently became an expert in this particular type of warfare, and was appointed to a post specialising in this field, serving on a number of capital ships. In May 1933 he was promoted to commander and took charge of the First World War destroyer . In December 1933 Walker took command of the sloop Falmouth based on the China Station. In April 1937 Walker became the Experimental Commander at HMS Osprey. Second World War When the Second World War began, in 1939, Walker's career seemed at an end. Still a commander, he had been passed over for promotion to captain and indeed had been scheduled for early retirement. He gained a reprieve, however, due to the commencement of war and in 1940 was appointed as Operations Staff Officer to Vice-Admiral Sir Bertram Ramsay. Even so, Walker still had not been given a command, despite expertise in antisubmarine warfare that would no doubt be indispensable in the Battle of the Atlantic. During Walker's time in that role the Operation Dynamo evacuation took place from Dunkirk, in which the British Expeditionary Force (BEF) was evacuated from France. The evacuation was a success