The barrage attack was developed during the Battle of the Atlantic in World War II as an anti submarine measure. It was first used by 2 Support Group of the Royal Navy after being developed by the Group's commanding officer, Captain "Johnnie" Walker. The barrage was expensive of resources, and could quickly empty an escort’s magazine, so it could only be used on stubborn cases. The practice of equipping convoy ships with reserves of depth charges to re-arm escorts when necessary went some way to alleviate this problem.