Royal Air Force on Eagle Day
Aircrafts and bases of the RAF squadrons in August 1940

The first phase of the German plan for the invasion of England was to gain control of the air and so during the months of July and August 1940 the RAF prepared its forces for the inevitable battle against the Luftwaffe.

The main defence possessed by the British was RAF Fighter Command which was under the inspired leadership of Air Chief Marshal Sir Hugh Dowding. The country was divided into four large areas to be defend by fighter groups, the most important being 11 Group under the command of Air Vice-Marshal Keith Park. This Group covered London, the Home Counties and south-east England, the fighting areas of the Battle of Britain.
Underneath th Group was the sector (nine in 11 Group) which would control anything from two to five squadrons. In some sectors all the squadrons would be based on the one airfield, in others they would be spread out over as many as four airfields. A typical sector was Northolt which was organised as follows:
No. 1 Sqdn - 10 Hurricanes;
No. 275 Sqdn - 13 Hurricanes;
No. 604 Sqdn - 10 Blenheim heavy fighters;
No. 609 Sqdn - 15 Spitfires.

By the end of July the RAF had 530 Hurricanes and Spitfires fighter aircraft ready for combat out of a total of just over 600, with another 289 fighters in reserve. Before Eagle Day, on 11 August 1940, there were 960 fighter planes ready for combat. Of these 704 were Hawker Hurricanes and Supermarine Spitfires (plus 289 reserve planes). Eagle Day ('Adlertag') on 13 August 1940 was the launching of the great Luftwaffe offensive planned to destroy RAF Fighter Command in four days.

Picture: Hurricane pilots 'scramble' on Eagle Day.

The RAF had considerable advantages over the Luftwaffe, the chief of these being a flexible command structure which ensured resources were not wasted; an integrated radar system which usually enabled RAF fighter pilots to intercept the German bomber squadrons; and the advantage of fighting over home territory.
The margin of the RAF's victory over the German Air Force was slim but it was sufficient to deter the Wehrmacht from seriously contemplating an invasion of Britain.

Active RAF Squadrons on Eagle Day (13 August 1940):

Note: Squadron Nos. 400 to 499 were squadrons of the Royal Canadian Air Force, Royal Australian Air Force and Royal New Zealand Air Force. Not all numbers were used and unfortunately there are no detailed information available.

Overview of RAF squadrons equipment and location:

The RAF squadron strength was between 6 and 18 aircrafts.

• see also Battle of Britain