Captain Frederick John 'Johnnie' Walker (DSO & 3 bars) is Britain's most famous U-boat hunter of World War II. 'On the shelf' in the interwar years (meaning he was repeatedly passed over for promotion), the trained anti-submarine warfare specialist won the attention of the Admiralty for his conduct assisting in the evacuation of Dunkirk in 1940.
As a lieutenant-commander, he was rewarded with the command of the long-range escort sloop HMS Stork in 1941. There he immediately applied his knowledge, forging his rag-tag squadron of old destroyers and Flower-class corvettes - the 36th Escort Group - into a well disciplined fighting unit.
Walker won fame in the defence of Convoy HG-76 (18023 December, 1941) which is credited as representing the 'turn of the tide' against Hitler's U-boat wolfpacks. Five U-boats were sunk, three of them by Walker's 36th Escort Group.
He was promoted to Captain shortly thereafter.