Why did Britain win the Battle of Britain in 1940?

Transcript
An Air Ministry note summarising Sir Hugh Dowding's report on the Battle of Britain, October 1941

Catalogue ref: AIR 20/5202

[Additional information appears in square brackets]

BATTLE OF BRITAIN
NOTE ON DESPATCH BY AIR CHIEF MARSHAL, SIR HUGH C.T. DOWDING

The outstanding feature of Sir Hugh Dowding's Despatch is that it constitutes a testimonial to the efficiency of the Air Defence System of Great Britain. This System had been planned before the war and developed within the resources which were made available; resources which were gradually increased as time wore on, as the threat became more acute, and as anticipation became realisation. This system must surely be the most highly developed form of Air Defence ever organised and it is clear that it was a decisive factor in the Battle of Britain.

Sir Hugh Dowding's Despatch briefly describes the components of this system. The active side with its fighters, A.A. [anti aircraft] guns, searchlights and balloons; the passive side with its radiolocation [radar], observer corps, air raid warnings and. the intricate air raid reporting system. These facts are clearly and simply set out in Part I of the Despatch. It is an impressive narrative enhanced by the simplicity of its treatment. It was this system, under the unified command of Sir Hugh Dowding himself, which brought about the defeat of the GAF [German Air Force] and thus prevented the enemy from undertaking an invasion of this country in 1940.

A number of difficulties and problems arose during the course of the Battle and these are detailed in the despatch. These difficulties and problems are common to most situations where hard fighting is the order of the day. They include such questions as shortage of reinforcement aircraft and personnel and modernisation of equipment to meet changes in the enemy's tactics. The components which go to make up the system require amendment [change] in the light of experience and constant modernisation, strengthening, and reinforcement as the war goes on. This is all in hand. The main basis of the system, however, has stood the test of time. It was designed to meet an emergency and succeeded in its task without any major amendment. This is the main conclusion we can draw from the despatch and, although we are not concerned with giving credit to those who are responsible, it is clear that the Air Staff correctly appreciated the situation so far as the Air Defence of this country is concerned.