Introduction to the Phases of the Battle of Britain
“…I expect that the Battle of Britain is about to begin…”
Winston S Churchill
In the United Kingdom the Battle of Britain is recognised officially as having taken place between 10th July and 31st October 1940.
The Germans do not recognise these dates in the same way. 
Different historians have described the progress of the Battle in different ways, but it is possible to identify five main phases, which started soon after the Luftwaffe had regrouped and consolidated its position following the defeat of France. Although they have been given precise dates one phase often drifted into the next and they should not be treated as hard and fast.
26th June to 16th July
Scattered and limited day and night attacks and mine-laying sorties, directed mainly against ports and shipping and towns with aircraft factories.
17th July to 12th August
Increasing and larger daylight attacks against shipping in the English Channel, ports along the South and East coasts and some coastal airfields, with increased night attacks against the West, Midlands, and East Coast, RAF facilities and the aircraft industry. 
Battle of Britain – Phase Three
13th August – 6th September
Large-scale daylight attacks against RAF airfields in South-East England, with the object of exhausting the RAF’ ability to provide a defence. Night attacks continued.
Battle of Britain – Phase Four
7th September – 2nd October
Large-scale day and night attacks against London.
Battle of Britain – Phase Five
3nd October – 31st October
Smaller scale daylight fighter-bombers attacks while large-scale night attacks continued mainly against London.
This was also the start of what came to be called the ‘Blitz’ on the capital and against other cities and towns, which lasted until May 1941.