What was Britain's main contribution in World War II?

The British intelligence department is civilized in the world, and the intelligence network can be said to have penetrated into the Nazi interior. British intelligence services made great contributions to the success of Allied landings in Normandy. On the battlefield in North Africa, the British general Montgomery led the army to repel Rommel, the fox of the desert, in Alaman, which bankrupt the German plan in North Africa. Britain's insistence on the British Isles forced Hitler to face the situation of fighting on two fronts, which created conditions for the allied forces to March into Western Europe and open the gap. Finally, when attacking Berlin, the British army also cleared the way for the Allied invasion of Germany.