 In August 1939, in a final effort to contain Germany, Britain and France guaranteed Polish independence (Anglo-Polish military alliance).Upon the outbreak of war in September 1939, British rearmament was not yet complete, although the Royal Air Force had been greatly expanded and programmes for new aircraft and equipment such as radar defences were just coming to fruition.Britain remained incapable of offensive operations except for strategic bombing, and this was relatively ineffective in the early war.