Complex sentence: The British commanding officer was Vice-Admiral Bertram Ramsay of the Royal Navy who was allocated six torpedo-equipped destroyers, which should have been on four hour standby in the Thames Estuary but were not.
Split into simpler sentences: The British commanding officer was Vice-Admiral Bertram Ramsay of the Royal Navy. Available for him were six destroyers, which should have been on four hour standby in the Thames Estuary but were not.