Any war in Europe involving Britain could threaten the security of her Empire.
During the 1930s the British Empire had come under threat from:
There were serious doubts that the armed forces could defend the Empire. Particularly if they were faced with problems in different areas at the same time.
Furthermore Britain had to deal with trouble in:
By the time of the Munich Crisis, the Dominions (Australia, New Zealand, Canada and South Africa) had concerns about Britain going to war over Czechoslovakia. Only New Zealand had given a firm guarantee of support. This increased the pressure to avoid a conflict in Europe.