The Battle of the Blockade was a Second World War naval battle, fought between ships of the Royal Navy and the Kriegsmarine, on 7th November, 1940. The battle is considered a major defeat for the British, and affected Allied naval strategy for the rest of the war and beyond.
British ships blockading German ports on the North Sea were attacked by a German fleet sailing from Wilhelmshafen, led by the German aircraft carrier Graf Zeppelin and the dreadnoughts Bismarck and Tirpitz. The Kriegsmarine force was successful in sinking two Royal Navy dreadnoughts and two monitors and damaging several other ships, while suffering the loss of only some airplanes.
The German victory in the battle is attributed to their success in feeding the British inaccurate information, and faulty British naval strategy. At the time of the battle, all British aircraft carriers were deployed in the Mediterranean, leaving the blockading ships with inadequate air cover, while the Admiralty believed that the German carrier was not able to conduct offensive operations. After the battle, Allied naval planning made sure that no area of operations was without proper air cover, either land or carrier based, which led to the original cancellation of the Lion-class and the suspension of all work on dreadnoughts in favour of aircraft carriers.