How was allied radar used in World War 2?

In 1940, the British had a chain of inter-linking radar sites along their coast lines and this provide early detection of enemy bombers during the highlight of what was known as the Battle of Britian. They could detect where the bombers were and their speed and this would allow the British to send their fighters to attack at the time and place of their choice. This allowed them to conserve fuel and aircraft and get a them back to re-arm and attack again. The Allied navy had radar on some of their ships. The Italian navy had no radar and were easily defeated, especially at night battles.