Although British forces went into action at the very outset of World War II in 1939, it was not until 1940 that the land war began.
This marked the beginning of a period of defeat; first Norway, then the Low Countries and finally France, culminating in the miraculous evacuation of what was left of the British forces off the beach at Dunkirk.
In the Mediterranean, British forces had to be hastily evacuated off Crete. In North Africa, early hopes were shattered by the arrival of the Afrika Korps under Erwin Rommel.
But salvation was at hand.
The turnaround began with the battle of El Alamein, followed by the invasion of Algiers and Tunisia. Victory in 1943 paved the way for the invasions of Sicily and Italy and then, in June 1944, Operation Overlord and the return of Britain and her Allies to continental Europe.
Victory came at a price. Defeat at Arnhem meant that the war in Europe would have to continue for another six months.
The final defeat of Germany began with the massive airborne assault across the Rhine, the largest ever seen. Within weeks, British forces were celebrating the German surrender having advanced all the way to the Baltic.
Fascinating archive film recalls these vital moments in a compelling and informative film.
British Battles of World War II is also available in the Britain at War eight-disc box set.