There were four significant phases that took place during World War 2's Battle of Britain during 1940:
1. July 10th to August 7th
The first phase involved German forces scouting the English Channel with its air forces. During this time, the Luftwaffe began attacking British trade ships as well as radar posts that dotted the landscape of southern England. Although these raids were light, the Luftwaffe was trying to find weaknesses in the British landscape.
2. August 8th to September 6th
The next step involved German forces attempting to severely cripple the "11 Group" RAF forces. This involved continuous raids that crippled the RAF forces; however, the RAF still hung on by defending their positions. Although the RAF became stretched due to limited supplies and many casualties, they still held their ground and would often use civilian airfields as a last resort.
German forces also engaged in night air raids in which they would bomb several areas. By accident, German forces bombed parts of London, which was against direct orders of Hitler. From these bombings, the English people became resolved to continue fighting and retaliated by bombing Berlin later in the war.
3. September 7th to October 5th
After Britain bombed Berlin, Hitler changed his tactics from destroying the RAF to targeting Britain's industry. If the Germans could hinder British production of airplanes, the Germans believed that could quickly end the conflict. This proved to be a grave mistake as it allowed the 11 Group to resupply and repair their bases as well as their planes.
In addition, Germany continued night raids and would often send large forces of bombers to attack production centers as well as bomb London. The RAF was able to confront these bombers in large numbers and inflicted heavy casualties to Luftwaffe forces. Probably the most decisive day during this time was September 15th in which British forces would secure a huge victory against German forces.
4. October 6th to October 31st
Luftwaffe forces continued night air raids by bombing major cities such as London and inflicted significant damage. During this time, British forces had recently equipped their fighters with radar to deal with these night raids and were successful in destroying many bombers. Eventually, German forces realized that the Battle of Britain could not be won and withdrew by October 31, 1940.