Why did Britain Need Coastal Defences during World War II?

  • In September 1939 Great Britain and France entered the Second World War against Germany.
  • Britain deployed an army, the British Expeditionary Force (BEF), in northern France in support of its ally and relatively little thought was given to the idea that Britain could be invaded.
  • This changed dramatically in April and May 1940 when Germany attacked Norway, Denmark, the Low Countries and France using a new form of warfare - Blitzkreig 'Lightning War' - characterised by high tempo operations involving fast moving formations of tanks and armoured vehicles supported by paratroopers, artillery and aircraft.
  • Germany achieved a total victory and the BEF was forced to evacuate France via Dunkirk, leaving most of its equipment behind.
  • There was now a real chance that Britain would be invaded by the victorious German army.
  • In the summer and autumn of 1940 the defence of Britain primarily rested on the Royal Air Force but, at the same time, the vulnerable coastline would have to become the front line in the defence of British soil.


German Attack

Map showing the German assault on France and the Low Countries, 1940