The Battle of Britain was a decisive air campaign fought over southern England in the summer and autumn of 1940.  It was one of Britain’s most important victories of the Second World War because it showed Germany could be defeated, it allowed Britain to carry on fighting the war, and ultimately ensured the Allies had a base from which to launch the liberation of Europe on D-Day in June 1944.

The timeline of the Battle of Britain can be divided into several stages, beginning with the Luftwaffe attacks in the Channel before moving inland to focus on the RAF airfields.

Here are 8 important dates from the Battle of Britain. 

German Stuka bomber releasing bombs. Photograph from the Battle of Britain.
© IWM GER 18
12 AUGUST 1940

On 12 August 1940 the Luftwaffe (German Air Force) began a systematic assault on RAF (Royal Air Force) Fighter Command's forward airfields and radar stations, striking at Manston, Lympne and Hawkinge aerodromes in the south-east and radar installations in Kent, Sussex and on the Isle of Wight.

This was their first major attack on Fighter Command's ground organisation. The airfields suffered different degrees of damage but were all serviceable by the next morning. Most of the radar stations were also quickly back on air, except Ventnor on the Isle of Wight which was seriously damaged.

These attacks displayed features which would characterise the fighting in the days ahead. There were several major raids, involving hundreds of aircraft, and attacks were timed to coincide with or closely follow one another, often on widely dispersed targets. Bombers, including the Junkers 87 or 'Stuka' dive bomber (pictured here) were heavily escorted by fighters.

Soldiers examine an MG 15 machine gun from a German Dornier Do 17Z bomber shot down during the Battle of Britain.
© IWM HU 89288
13 August 1940

For the Germans, 13 August 1940 marked the start of their Battle of Britain. They called it 'Adlertag' (Eagle Day). Waves of strong attacks over a ten-hour period came in against Essex, Kent, Sussex and Hampshire. On 'Eagle Day' the Luftwaffe mounted a total of 1,485 sorties (missions) with Fighter Command flying 727 sorties in response.

The German intention was to probe British defences to see if they could direct equal resources against widely separated attacks. They saw only moderate success. Southampton experienced some damage and the only airfields to suffer, Eastchurch and Detling, were Coastal Command stations which left British fighter defences unimpaired. Three main Luftwaffe objectives - Odiham, Farnborough and Rochford - were completely missed. However, the day's operations also demonstrated the difficulty British defences had in meeting the Germans with forces large enough to inflict significant losses.

In this photograph, British soldiers examine a German MG 17 machine gun and part of the tail assembly of a Dornier Do 17, shot down over the Thames Estuary during the attacks on Eastchurch aerodrome in south-east England on 13 August.

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Battle of Britain pilot Flight Lieutenant Eric Nicolson VC photographed in hospital where he was recuperating.
© IWM CH 1700
16 August 1940

The Luftwaffe made a similarly massive effort the following day, 16 August, with three assaults over Kent and the Thames Estuary, Sussex and Hampshire, and at four different points between Harwich and the Isle of Wight. The pattern of raids was very similar to 15 August, with the strongest German activity directed against Fighter Command. The Luftwaffe's intelligence shortcomings meant that only three of the eight airfields attacked, Manston, West Malling and Tangmere were fighter bases.

During an action near Southampton on 16 August 1940, Flight Lieutenant James Nicolson (pictured here three months later) was wounded when his Hurricane was attacked by a Messerschmitt Bf 110. Despite his cockpit being on fire, he attacked and shot down another German fighter, suffering serious burns before bailing out. For his actions he became Fighter Command’s only recipient of the Victoria Cross during the Second World War.

RAF aircraftmen guard the remains of a German Dornier bomber shot down during the Battle of Britain
© IWM HU 70268
18 August 1940

After their major efforts on 15 and 16 August, the Germans paused to recover before returning in force on 18 August. Flying 750 sorties, the Germans attacked airfields at Biggin Hill, Kenley, Croydon and West Malling. The raid on RAF Kenley caused severe damage. All ten of its hangars and several aircraft – mostly Hurricanes – were destroyed. In this photograph men of the RAF guard the remains of a Dornier Do 17 shot down during the attack on Kenley. The Germans also bombed the Isle of Wight, destroying an important radar station. Another large scale attack fell on Kent in the late afternoon.

The Germans suffered for their efforts. The losses of Junkers 87 'Stuka' dive bombers were so severe that this aircraft was largely withdrawn from the main battle.

A Halifax B Mark VI bomber
© IWM ATP 13205D
30 August 1940

On 30 August during a period of direct assaults against RAF sector stations across the south-east, Fighter Command flew 1,054 sorties - its largest daily number yet. Twenty-two fighter squadrons saw action, most at least twice and some up to four times. The Germans flew 1,345 sorties, their biggest daylight effort for a fortnight. The tempo of combat was increasing daily and for the British 30 August was the heaviest day of fighting they had experienced so far.

The first main raid, flying in across Kent and Sussex, began at 10.30am. At 1.30pm successive waves of German bombers came in over southern Kent and the third and largest raid began around 4.00pm. Biggin Hill suffered severe damage – one of the last remaining hangars was destroyed and most telephone lines, gas, electricity and water mains were cut. Attacks on the Vauxhall factory at Luton also caused substantial damage, although those on the Handley Page Halifax bomber production line at Radlett, pictured here later in the war, did not.

Sergeant Joan E Mortimer, Flight Officer Elspeth C Henderson and Sergeant Helen E Turner, recipients of the Military Medal for gallantry, standing outside damaged buildings at Biggin Hill, Kent. All three were WAAF teleprinter operators who stayed at their posts and continued to work the defence lines during the heavy Luftwaffe attacks on Biggin Hill on 1 September 1940.
© IWM CH 1550
31 August 1940

On 31 August the Germans mounted an even larger operation. It was costly for both sides and Fighter Command’s losses were the heaviest of the whole of the Battle of Britain - 39 aircraft shot down and 14 pilots killed. Early waves of attacks came in over Kent and the Thames Estuary, targeting the airfields at North Weald, Debden, Duxford and Eastchurch. The next attack focused on RAF Croydon, Biggin Hill and Hornchurch, with the latter two attacked again later in the afternoon. Both airfields were serviceable by the following day, but the cumulative damage at Biggin Hill meant two of the three squadrons based there were put under the control of nearby sectors.

Biggin Hill was also attacked on 1 September and in this photograph Sergeant Joan Mortimer, Corporal Elspeth Henderson and Sergeant Helen Turner of the Women's Auxiliary Air Force (WAAF) stand outside the station's damaged buildings. All three were awarded the Military Medal for gallantry. They stayed at their posts during the raid and Sergeant Mortimer also marked unexploded bombs with flags. This was Biggin Hill's sixth raid in three days. It was bombed again on 5 September 1940.

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A Heinkel He 111 bomber flying over the Isle of Dogs in the East End of London during the Blitz
© IWM C 5422
7 September 1940

On 7 September, after a fortnight of assaulting vitally important RAF sector stations in the south-east with considerable success, the Germans suddenly changed their tactics and launched an all-out attack on London. Germany felt that the sector stations had suffered sufficient damage and that, with time running out in which to launch a successful invasion of Britain, the most rapid conclusion to the Battle of Britain could be reached by focusing effort on the capital. Fighter Command would be certain to defend the capital in the greatest possible strength, so targeting London offered the unique chance for a huge and decisive air battle.

German fighters provided close escort support for the bombers and the sheer size of the German force meant many of the raids were successful in hitting targets in the capital. The Germans laid waste to large areas of the London docks, Woolwich Arsenal, Beckton gasworks, West Ham power station and the oil storage tanks at Thameshaven. A second wave hit Millwall, the commercial docks at Tilbury and Thameshaven and the heavily populated streets of the East End. The fires from the burning buildings were perfect markers for the bombers which continued to come throughout the night and for the next nine months - what became known as the 'Blitz'. Despite the damage the raids on London caused  the German decision to shift the focus of attacks away from RAF targets was a tactical error of such importance that it was arguably the turning point of the Battle of Britain.

A newspaper seller in the street watching a "dog-fight" during the Battle of Britain.
© IWM HU 810
15 September 1940

A week after their change of tactics, the Germans launched another massive assault on 15 September, which they believed would finally shatter Fighter Command’s resistance and open the way for a successful invasion. However, since 7 September Britain's defences had recovered, fighter production continued and operational pilot strength was the highest it had been since the start of the Battle of Britain.

The German offensive came in two distinct waves, giving British aircraft time to refuel and rearm. Also, the usual diversionary manoeuvres were not employed so the British were able to deploy as many as 17 squadrons - in good positions - to meet the threat. German bomber formations were smashed, making accurate bombing impossible. Although bombs were dropped on London, Portland and Southampton, little damage was done. Some of the fighting in the skies was visible from the ground and this photograph shows how closely the dogfights between the RAF and the Luftwaffe were followed during the battle.

It was a day of heavy and sustained fighting and the Germans suffered their highest losses since 18 August. It was obvious to both sides that German tactics had failed and the Luftwaffe had not gained the air supremacy they needed for an invasion. Fighting continued for another few weeks, but the action on 15 September was seen as an overwhelming and decisive defeat for the Luftwaffe. For this reason, this date is celebrated in the United Kingdom as Battle of Britain Day.