Both the Allies and Axis powers used radar in the Second World War, with the conflict greatly influenced by it.
Countries had been developing the revolutionary new technology since the mid-1930s, and by the time of the outbreak of war, both Germany and Britain had working systems.
But it was the Royal Air Force who made better use of it. By mid-1940, the RAF had fully integrated radar into the nation's air defence.
Germany, on the other hand, had neglected it, due to failings by the Luftwaffe and Adolf Hitler's disdain for defensive measures.
In this archive feature, we look at how advances in radar technology helped lead the Allied forces to victory in the skies, including in the Battle of Britain.