Since the defeat of the Spanish Armada in 1588, the British people have confronted no greater threat to their freedom than in 1940, when Hitler's armies swept through France in a few scant weeks and stood poised twenty-one miles from Dover. Had the Luftwaffe then gained air supremacy over the English Channel, nothing could have prevented the first invasion of Britain in over 900 years. This is the story of how Britain turned the prevailing tide, against all the odds - and won the day. Illustrated with photographs from private collections, drawings, diagrams and charts that clarifies the day by day events on both sides accompanied by text from witnesses and combatants that evoke those few desperate weeks of human endeavour and how the delicate balance was tipped - only just - in Britain's favour.