It inspired one of Prime Minister Winston Churchill's most famous speeches: "Never before, in the field of human conflict has so much been owed by so many to so few."
Why is it called the Battle of Britain?
Adolf Hitler explored military options that would bring World War Two to a quick end and ordered his armed forces to prepare for an invasion of Britain – codenamed Operation 'Sealion'.
German bomber aircraft, escorted by fighter planes, made their way across the Channel to bomb Britain.
The Germans began by attacking coastal targets and British shipping operating in the English Channel.
They launched their main offensive on 13 August.
Using a network of radar systems and communications telling them when and where the Germans were planning to attack, the RAF, led by Sir Hugh Dowding, shot down many German bombers before they could cause huge amounts of damage.
The Luftwaffe (German Air Force) was defeated by Fighter Command, forcing Hitler to abandon his invasion plans.
In avoiding defeat, Britain secured one of its most significant victories of the Second World War and it was able to stay in the war.
Who helped Britain?
About 3,000 men of the RAF took part in the Battle of Britain – those who Winston Churchill called 'The Few'.
Although most of the pilots were British, Fighter Command was an international force: The British were joined by pilots from countries including Australia, New Zealand, Poland, Canada, South Africa and France.
While victory in the Battle of Britain was decisively gained by Fighter Command, defence was carried out by the whole of the Royal Air Force which was organised into different 'Commands' based on function or role.
Many others on the ground also worked to defend Britain – ground crew, factory workers, The Observer Corps which tracked incoming raids, anti-aircraft gunners, searchlight operators and barrage balloon crews.
Watch: What was the Dowding System, and why was it so important to the Battle of Britain?
Members of the Women's Auxiliary Air Force (WAAF) served as radar operators and worked as plotters, tracking raids in the group and sector operations rooms.
The Local Defence Volunteers (later the Home Guard) had been set up in May 1940 as a 'last line of defence' against German invasion. By July, nearly 1.5 million men had enrolled.
How many people died?
Out of the 3,000 RAF pilots who signed up, 544 (about one in six) were killed.
2,500 Luftwaffe airmen lost their lives.
About 40,000 people had been killed by the time the campaign finally ended in May 1941, according to the RAF Benevolent Fund.
What happened next?
Once the Battle of Britain ended, the Luftwaffe focused on London, leading to the 'Blitz', which lasted from September 1940 to May 1941.
Eventually, Hitler abandoned the Blitz and most of the Luftwaffe was re-assigned east in preparation for Germany's invasion of Russia on 22 June 1941.