Final answer:
The period between October 1939-April 1940 in Britain is referred to as the 'Phony War' or 'Sitzkrieg', where there were preparations for war with Germany but no direct conflict on the Western Front.
Step-by-step explanation:
The period during October 1939-April 1940 called for the British was known as the 'Phony War' or 'Sitzkrieg'. After France and Britain declared war on Germany following the invasion of Poland, there was a phase where no significant ground battles were fought on the Western Front. This time was characterized by anticipation and preparation for war rather than direct conflict. Meanwhile, Britain was girding itself for the Luftwaffe assault which culminated in the Battle of Britain, starting in July of 1940. Although the intense phase of aerial combat known as the Battle of Britain started later, during the 'Phony War', Britain was monitoring events closely and preparing for the inevitable confrontation with Germany, as Hitler's military dominance in Europe was increasing rapidly.