Two major attacks on airfields. Serious damage to the Vickers Works at Brooklands.

Night: Further raid on Liverpool.

Weather: Fine and warm with haze in the Channel and Straits. Occasional rain and strong winds in the north.

Enemy Action by Day

By 4 September 1940, the Luftwaffe’s focus was beginning to evolve. While airfields remained primary targets, the first daylight attacks on British aircraft manufacturing facilities were now underway, following orders issued from Berlin on 1 September. The day saw two large-scale raids directed at airfields in East Kent and the Thames Estuary, while a separate formation struck the Vickers-Armstrong aircraft works at Brooklands, inflicting severe casualties. In the north and west, high-flying reconnaissance aircraft scouted convoys and key ports. Fighter Command responded aggressively, destroying 28 enemy aircraft. RAF losses stood at 17 aircraft, with 12 airmen killed or missing.

Morning Raids: Airfields in Kent and Essex Targeted

Shortly after 09:00 hours, the first coordinated raids of the day took shape as a force of some 150 aircraft crossed the Channel in two main groups. The larger, around eighty strong and composed chiefly of Bf 110s with fighter escort, drove into the Thames Estuary before turning inland toward Eastchurch, Hornchurch, North Weald, and Debden. The second, about seventy aircraft, crossed near Lympne and advanced on Biggin Hill. To meet the threat, Hurricanes of No. 111 Squadron scrambled from Croydon, while No. 253 Squadron took off from Kenley. Spitfires of Nos. 66 and 72 Squadrons were vectored toward the Estuary from Kenley and Croydon.

Eastchurch came under renewed attack, its runways cratered and several buildings damaged, though flying operations continued. Hornchurch and Debden were approached but not struck with significant force, while at Lympne bombs caused craters and structural damage, yet essential facilities were left intact. Escorting Bf 109s kept RAF fighters occupied long enough for several Bf 110s to reach their objectives. By 09:45, the main German force was already withdrawing across the Channel, though some thirty enemy aircraft lingered off North Foreland to harass RAF patrols.

Midday Assault: Fighter Command Responds

At 12:35 hours, five German bombers were sighted over Dover, and by 12:58 a major raid was developing. Radar stations at Dover and Rye soon plotted a large formation approaching the coast, and at 13:05 nearly 300 aircraft crossed the shoreline in a broad front stretching from Dover to Littlehampton at about 20,000 feet. The force comprised some fifty Heinkel He 111s, thirty Dornier Do 17s, and around 200 Bf 109s.

The RAF response was swift. Squadrons scrambled included No. 43 (Tangmere), No. 46 (Stapleford), No. 66 (Kenley), No. 72 (Croydon), No. 79 (Biggin Hill), No. 222 (Hornchurch), No. 249 (North Weald), No. 234 (Middle Wallop), No. 253 (Kenley), No. 601 (Tangmere), No. 602 (Westhampnett), and No. 603 (Hornchurch). Reinforcements were also provided by No. 73 Squadron, newly transferred from Church Fenton to Debden, and No. 41 Squadron, recently redeployed from Catterick to Hornchurch.

Heavy fighting broke out across Kent and the Thames Estuary. The sky over Sussex and Surrey was described as chaotic, with thick vapour trails hanging in the air. Two-thirds of No. 11 Group was engaged at once. At 13:20 hours, AVM Keith Park ordered squadrons to patrol key sector stations south of London and to reinforce North Weald, which was still recovering from previous raids.

Brooklands Bombed: Devastation at Vickers Works

With attention focused on high-level formations, radar failed to detect a small, low-flying force of fourteen Bf 110s from Erprobungsgruppe 210, following the railway line from Hindhead toward Guildford. Escorted by elements of V.(Z)/LG 1 and III./ZG 76, the formation penetrated deep into Surrey. Their intended target was the Hawker factory at Brooklands, but they mistakenly bombed the nearby Vickers-Armstrong Works at Weybridge—critical for the production of Wellington bombers.

As the Bf 110s closed in, anti-aircraft guns opened fire, bringing down two of the attackers. Even so, six bombers pressed home their attack, dropping their loads on the Vickers facility during the lunch hour. The results were devastating: eighty-eight workers killed, more than 600 injured, and Wellington production suspended for four days. Several erecting shops and critical plant machinery were destroyed, though the nearby Hawker factory escaped unscathed.

Hurricanes of No. 253 Squadron intercepted the German raiders north of Guildford, soon reinforced by Nos. 43, 601, and 602 Squadrons as the enemy turned for home. Over Worthing, Spitfires of No. 234 Squadron claimed fourteen Bf 110s and one Do 17 destroyed, with only a single aircraft damaged in return.

Heavy Losses and Notable Incidents

Among the Bf 110s lost was the machine flown by Oblt. Wilhelm Schäfer, adjutant of Stab.(Z)/LG 1. Forced to fly a replacement aircraft after his own had been damaged on 11 August, Schäfer became separated from his formation and was attacked by Spitfires over the Downs. His aircraft was shot down near Shoreham, crash-landing at Mill Hill. Both Schäfer and his radio operator, Uffz. Heinz Bendjus—wounded in the action—were captured and taken prisoner.

Despite the scale of their losses, Luftwaffe pilots still submitted numerous victory claims. Hptm. Erich Groth of Stab II./ZG 76 reported four Spitfires destroyed, while Oblt. Walter Borchers of 4./ZG 76 claimed three. Oblt. Hans-Joachim Jabs of 6./ZG 76 and Oblt. Wilhelm Hobein of 5./ZG 76 each claimed two. Fighter Command, meanwhile, recorded the loss of fifteen aircraft—nine Spitfires and six Hurricanes—with six pilots killed in action.

Late Afternoon Raids and Poling Radar Station Hit

At 14:00 hours, a formation of fourteen Bf 110 fighter-bombers from Erpr.Gr. 210 crossed the coast to strike the radar station at Poling. Their advance was covered by Bf 110s of V.(Z)/LG 1 and III./ZG 76, while II./ZG 76 conducted a free-ranging sweep further east. The raiders were intercepted by Spitfires of No. 234 Squadron and Hurricanes of Nos. 43 and 601 Squadrons, with Spitfires of No. 602 Squadron providing high cover. Later in the engagement, Hurricanes of No. 253 Squadron joined the action near Guildford.

In a running battle that raged for over an hour, RAF squadrons inflicted heavy losses on the enemy. Over Worthing alone, seven Bf 110s were destroyed. Further east, No. 1 (RCAF) and No. 79 Squadrons clashed with II./ZG 76 above East Grinstead, adding to the toll. By the end of the day, Fighter Command estimated that at least sixteen Bf 110s had been lost—an unsustainable rate of attrition for the Luftwaffe’s Zerstörer formations.

Enemy Action by Night

From 20:00 hours, night raids began across Britain. German bombers targeted Bristol, Cardiff, Swansea, Liverpool, Tilbury Docks, and Newcastle. In South Wales, oil storage tanks were struck, setting off fires visible across the region. Tilbury suffered a major fire at the Orient Line offices, though it was eventually brought under control. At Bristol, the aeroplane company at Filton was hit, but damage was limited. Four civilians were killed and six injured in the raid.

Bomber units taking part included He 111s of I./KG 27, Ju 88s of II./LG 1, and all three Gruppen of KG 51, along with aircraft from I. and II./KG 55 and I./LG 1. In all, more than 200 German aircraft operated over Britain during the night, with some formations believed to have carried out mine-laying missions along the coasts and estuaries.

Naval Losses and Further Damage

While the air war raged, E-boats attacked a southbound convoy off Cromer. The steamer SS New Lambton (2,709 tons) was sunk, along with the Joseph Swan, Fulham V, and Corbrook—each carrying coal from northeast ports to London.

Strategic and Political Developments

In Berlin, Adolf Hitler addressed a crowd at the Sportpalast. In a speech marked by defiant rhetoric and exaggerated claims, he mocked British air defences and warned of retribution for RAF night attacks. “Be calm,” he told the cheering audience, “He’s coming.” Behind the bravado, Luftwaffe commanders were preparing for a fundamental change: the bombing of London was imminent.

German Losses:
Airmen: 24 | Aircraft: 28

British Losses:
Airmen: 12 | Aircraft: 17

Hurricane R4172, No. 111 Squadron
F/L D.C. Bruce listed as missing. Crashed into Channel after combat with Bf 109.
http://www.bbm.org.uk/airmen/Bruce.htm

Hurricane Z2309, No. 111 Squadron
P/O J. Macinski listed as missing. Shot down by Bf 109. Pilot bailed out but body was never found.
http://www.bbm.org.uk/airmen/Macinski.htm

Spitfire N3048, No. 66 Squadron
Sgt A.D. Smith died of injuries 6/9/40. Bailed out with serious injuries after combat with enemy aircraft.
http://www.bbm.org.uk/airmen/SmithAD.htm

Hurricane V6638, No. 253 Squadron
F/O A.A.G. Trueman killed. Shot down during combat action over Kenley aerodrome.
http://www.bbm.org.uk/airmen/Trueman.htm

Hurricane P3052, No. 46 Squadron
F/O R.P. Plummer died of injuries 14/9/40. Shot down in flames by Bf 110. Pilot bailed out with serious burns.
http://www.bbm.org.uk/airmen/Plummer.htm

Spitfire X4278, No. 222 Squadron
P/O J.W. Cutts killed. Shot down by Bf 109. Aircraft crashed at Sutton Farm. Originally listed as missing but body fragments discovered at excavation of crash site. Now listed as KIA.
http://www.bbm.org.uk/airmen/Cutts.htm

Spitfire K9962, No. 222 Squadron
Sgt J.W. Ramshaw killed. Crashed after combat with Bf 109s. Was dead on arrival at West Kent Hospital.
http://www.bbm.org.uk/airmen/Ramshaw.htm

Hurricane P3676, No. 79 Squadron
Sgt J. Wright died of injuries 5/9/40. Shot down by Bf 110 over base. Pilot crash-landed aircraft at Surbiton.
http://www.bbm.org.uk/airmen/WrightJ.htm

Defiant N1628, No. 264 Squadron
F/O D.K.C. O’Malley killed.
http://www.bbm.org.uk/airmen/OMalley.htm
Sgt L.A.W. Rasmussen killed.
http://www.bbm.org.uk/airmen/Rasmussen.htm
Aircraft crashed during night landing practice.

Hurricane V7406, No. 151 Squadron
P/O R. Ambrose killed. Crashed into a crane during take off on ferry flight. Aircraft burnt out.
http://www.bbm.org.uk/airmen/AmbroseR.htm

Spitfire R6909, No. 151 Squadron
Sgt J.K. Barker killed. Possibly shot down by return fire from Do 17 over Channel. Body washed up on French coast.
http://www.bbm.org.uk/airmen/BarkerJK.htm

Photo Descriptions

1. A sergeant pilot in the cockpit of his Spitfire Mk I, demonstrating the firing button on the control column, September 1940. © IWM (HU 104502)
2. Spitfires of No. 222 Squadron scramble from RAF Hornchurch, September 1940.
3. Messerschmitt Bf 110C (M8+CP, W.Nr. 2089) of 6./ZG 76 was intercepted and shot down by Flying Officer R. Smither of No. 1 (RCAF) Squadron on 4 September 1940. The aircraft exploded in mid-air and crashed at Smarts Hill, near Penshurst, Kent. Both crew members—pilot Oberstleutnant Günther Piduhn and Gefreiter Rudolf Odene—were killed.
4. Messerschmitt Bf 110C-4 (M8+AC W.Nr. 3602) of Stab II./ZG 76 was damaged by No. 1 (RCAF) Squadron Hurricanes during an escort sortie and belly-landed in the garden of Little Butts Farm at Cousley Wood, near Wadhurst in Sussex at 1:35 PM on 4 September 1940. Pilot Oblt. Hermann Weeber and Bordfunker Uffz. Max Michael were both captured.