The alliance assumption behind British naval planning

British planners did not expect Norway and France to fall rapidly while Britain simultaneously faced Germany, Italy, and Japan. Their fleet plans assumed French help in Europe and probably French and Dutch help in the Far East. That coalition assumption allowed Britain to divide a two-ocean fleet among several stations without covering every enemy alone. France's collapse therefore created new threats and new commitments at the same time, making it a strategic shock rather than a routine contingency.