Three large raids in the south-east, including London. Portsmouth and Southampton attacked. German invasion postponed again (till the 14th).

Night: London and Merseyside attacked.

Weather: Mainly fine with some local showers. Cloud in the Channel and Thames Estuary.

Enemy Action by Day

This day marked the date originally scheduled for the launch of Unternehmen Seelöwe (Operation Sealion), the German invasion of Britain. In reality, Germany remained unprepared to mount such an operation. Britain’s coastal defenses stood firm; naval ports and supply depots remained operational, and RAF Bomber Command continued to inflict damage on invasion shipping gathered in French and Dutch ports. Repeated bombing raids on barge concentrations at Calais, Boulogne, and Ostend had reduced the Kriegsmarine’s invasion fleet. The Luftwaffe, tasked with breaking RAF Fighter Command and gaining air superiority, launched heavy raids during the afternoon in an effort to draw out and overwhelm British defenses.

Morning Reconnaissance and Early Activity

The morning hours were comparatively quiet. German reconnaissance aircraft were tracked over the Firth of Forth, off Yarmouth, and along the Humber Estuary. Over East Kent, six isolated patrols by single aircraft were reported before midday, one identified as a Henschel Hs 126. Sporadic flights were also noted over the Thames Estuary, but no concentrated raids developed.

By late morning, British radar stations detected several small formations assembling over Calais and Ostend. Fighter Command maintained a high state of readiness, with squadrons on fifteen-minute alert, as sector controllers anticipated the now-familiar tactic of massed, closely spaced waves of bombers and escorts.

The Afternoon Build-Up and Main Attacks

At 14:45 hours, radar picked up a large build-up of Luftwaffe aircraft between Calais and Ostend. Two main formations—each numbering approximately 150 aircraft—were detected crossing the Kent coast between Ramsgate and Deal, heading toward the Thames Estuary. The main force included Heinkel He 111s of KG 1 and KG 26, directed against London’s docklands and industrial districts. They were escorted by Messerschmitt Bf 109s of JG 51 and I.(J)/LG 2, with Bf 110s of ZG 26 providing close protection from bases in northern France. The Bf 110s were positioned to the flanks and rear of the bomber stream, while the Bf 109s maintained stepped cover at higher altitudes. This layered escort system was intended to shield the bombers along the Thames corridor, but repeated interceptions by RAF squadrons drew the fighters into combat and left the Heinkels increasingly vulnerable.

Fighter Command scrambled units from 11 Group, reinforced by elements of Leigh-Mallory’s 12 Group “Big Wing” and by 10 Group squadrons prepared to counter a simultaneous southern attack. Hurricanes of No. 1 (RCAF) Squadron from Northolt and No. 238 Squadron from Middle Wallop, together with Spitfires of No. 222 Squadron from Hornchurch, were among the first to engage the incoming formations over central Kent. Additional Hurricanes from Nos. 17, 46, 73, 249, 253, 303 (Polish), and 605 Squadrons, and Spitfires from Nos. 41, 66, 72, 74, 92, 266, and 611 Squadrons, were engaged across a wide front from the Thames Estuary to South London.

At 15:05 hours, two preliminary raids of around 20 and 6 aircraft crossed near Dover, climbing to 25,000 and 11,000 feet, respectively, while at 15:34 hours a massive force of 150–200 aircraft crossed near Folkestone at 15,000–20,000 feet, moving northwest toward Maidstone. Around 30 aircraft penetrated into central London, while another element veered toward Brooklands. These formations were met by four squadrons over the London approaches.

Heavy Fighting over Kent and London

Over the Thames Estuary, fierce engagements developed. Spitfires of No. 74 Squadron attacked He 111s head-on, while Nos. 266 and 611 Squadrons targeted the fighter escort. Squadron Leader B.J.E. Lane of No. 19 Squadron led a head-on attack against the lead Heinkels, damaging one and setting a Bf 110 alight over Sittingbourne. Flying Officer L.A. Haines of No. 19 Squadron attacked a defensive circle of Bf 110s but was forced to crash-land after his Spitfire sustained heavy damage.

No. 303 (Polish) Squadron, flying Hurricanes from Northolt, joined No. 229 Squadron over the Horsham area and attacked the rear of the bomber stream. The Polish pilots claimed significant victories: Flight Lieutenant Forbes destroyed two Do 17s; Flying Officer Henneberg downed one He 111 and one Bf 109; Pilot Officer Zumbach claimed a Bf 109; Flying Officer Lokuciewski destroyed a Do 17 and a Bf 109; and Flight Lieutenant Paszkiewicz accounted for a Bf 110. Several other Polish pilots, including Sergeants Szaposznikow and Brzozowski, each claimed multiple kills against He 111s and Bf 110s.

The Luftwaffe’s primary bombing targets were London’s docklands, Woolwich Arsenal, and industrial facilities. Fires and damage were reported across Surrey Commercial Docks, Lewisham High Street—where a public shelter was hit, causing around 100 casualties—and Deptford Central Hall, which collapsed with 50 people trapped beneath the rubble. Warehouses, gasworks, and railway facilities sustained further damage.

Portsmouth and Southampton Attacked

While the main assault on London was underway, Luftflotte 3 launched a coordinated raid against Portsmouth and Southampton at 16:10 hours. The attacking force comprised nine Bf 110 fighter-bombers of Erprobungsgruppe 210, supported by close escort from II. and III./ZG 76, with further Bf 110s of V(Z)/LG 1 and ZG 2, and high cover provided by Bf 109s of I. and III./JG 27, together with elements of JG 2 and II./JG 53. Their objective was the Supermarine and Cunliffe-Owen works at Eastleigh and dockyard installations in the Solent.

Hurricanes of No. 213 Squadron from Tangmere were ordered to engage the fighter-bombers, while Spitfires of No. 602 Squadron from Westhampnett took on the escort, and Hurricanes of No. 607 Squadron from Tangmere were held to guard the sector base. Contact was made five miles east-southeast of Selsey Bill, where fierce combat developed. Eight Bf 110s dive-bombed the Cunliffe-Owen Aircraft Works at Eastleigh, causing heavy casualties when a shelter was struck, killing 52 and injuring many more. Eastleigh Naval Air Station was also dive-bombed at approximately 16:13 hours but escaped serious damage.

Evening Actions and Smaller Raids

From 17:00 hours, smaller raids were reported over Kent, with single aircraft striking airfields at Colerne, Kenley, Detling, and Eastchurch, though damage was light. A coastal convoy, Peewit, was dive-bombed off Margate and Dover by Ju 87s of Sturzkampfgeschwader 1, escorted by III./JG 26 “Schlageter.” RAF fighters scrambled to protect the convoy included Spitfires of Nos. 54 and 603 Squadrons from Hornchurch, as well as Hurricanes of No. 501 Squadron from Gravesend, with additional patrols by other 11 Group units already airborne in the sector. Intense engagements developed over East Kent. Oberleutnant Joachim Müncheberg of 7./JG 26 destroyed a Spitfire east of Ashford at 19:25 hours, his nineteenth victory. Five minutes later, Leutnant Gustav Sprick of 8./JG 26 shot down a Hurricane near Canterbury, his seventeenth confirmed success. Other pilots of III./JG 26 also submitted claims during the action, while Royal Navy records noted that the convoy escort Atherstone was damaged during the raid.

As the German formations withdrew, they encountered a Coastal Command formation of Blenheims returning from an anti-shipping raid on Calais. III./JG 26, led by Hauptmann Gerhard Schöpfel, intercepted and shot down one of the Blenheims—his twentieth victory—earning him the Ritterkreuz upon return to base. Pilots from III./JG 53 and I./JG 52 also claimed multiple Blenheims during this encounter, including Oblt. Günther Büsgen of 1./JG 52 and Oblt. Walter Fiel of 8./JG 53—each credited with two kills.

Enemy Action by Night

Night operations began at 20:20 hours as raids from Le Havre and Dieppe crossed the coast between Beachy Head and Shoreham. While many of these raids failed to penetrate London’s anti-aircraft barrage, others approached from Cherbourg, striking the Bristol Channel and crossing Wales toward Liverpool and the Merseyside docks. From 23:45 hours, isolated aircraft penetrated London from Dungeness, returning via Tangmere. By 03:00 hours, the southern raids ceased, but new attacks approached London from the northeast via the Dutch Islands, continuing until about 05:00 hours.

London’s docklands, central districts, and Buckingham Palace were all targeted. Damage to Buckingham Palace prompted Queen Elizabeth to famously remark:

“Now the palace has been bombed, I can look the East End in the face.”

Fires broke out across Finsbury, Holborn, and Bermondsey. The Stab of KG 55 lost a He 111 after a crash-landing at Villacoublay on return from the raid.

Losses and Claims

The day’s fighting proved costly. Fighter Command lost 29 aircraft, with 18 pilots killed and four severely injured. Luftwaffe losses totaled 29 aircraft, with KG 26 losing eight He 111s and several Bf 109s and Bf 110s shot down or force-landed.

Among German claims, Major Werner Mölders of Stab./JG 51 shot down a Spitfire southeast of London, while Major Adolf Galland of Stab./JG 26 downed a Hurricane northwest of Dungeness. Double victories were claimed by Oblt. Herbert Ihlefeld (2./LG 2), Ofw. Siegfried Schnell (4./JG 2), and Oblt. Hermann-Friedrich Joppien (1./JG 51). Other successful Luftwaffe pilots included Oblt. Hans Hahn (4./JG 2), Uffz. Kurt Bühligen (6./JG 2), Hptm. Eduard Neumann (I./JG 27), Oblt. Gerhard Homuth (3./JG 27), Oblt. Gustav Rödel (4./JG 27), Hptm. Walter Oesau (III./JG 51), Hptm. Wolf-Dietrich Wilcke (III./JG 53), Oblt. Kurt Brändle (4./JG 53), Oblt. Hubertus von Bonin (I./JG 54), and Oblt. Hans-Joachim Jabs (6./ZG 76).

Home Security Reports

Home Security records show extensive damage to London’s docks and telecommunication facilities. The Central Telegraph Office at St. Martin’s-le-Grand sustained heavy damage at 20:42 hours, while Poplar’s Manganese Bronze and Brass Company Wharf was hit by HE bombs at 23:33 hours. Fires gutted the Star Works of Thomas De La Rue Ltd. in Bunhill Row. Rail transport was severely disrupted: the Southern Railway line at Bickley was blocked by five HE bombs at 01:30 hours on 12 September, and Crystal Palace Low Level Station suffered major bomb damage at 02:10 hours.

Dover was shelled from France between 15:52 and 16:01 hours, with 26 shells causing significant property damage and casualties—seven killed and twelve seriously injured.

Ground casualties from enemy action on this day amounted to 53 killed and 321 injured, with the docklands and public shelters among the worst-hit areas.

German Losses:
Airmen: 35 | Aircraft: 29

British Losses:
Airmen: 18 | Aircraft: 29

Hurricane P3525, No. 46 Squadron
Sgt S. Andrew killed. Crashed and burnt out for reasons unknown after an uneventful patrol.
http://www.bbm.org.uk/airmen/Andrew.htm

Hurricane V7232, No. 46 Squadron
Sgt W.A. Peacock listed as missing. Failed to return after combat action. Presumed crashed into the sea.
http://www.bbm.org.uk/airmen/PeacockWA.htm

Hurricane P3770, No. 504 Squadron
P/O A.W. Clarke listed as missing. Crashed and burnt out near Newchurch after combat over coast.
http://www.bbm.org.uk/airmen/ClarkeAW.htm

Spitfire P7298, No. 611 Squadron
Sgt F.E.R. Shepherd killed. Caught fire during combat. Pilot baled out but aircraft crashed into houses.
http://www.bbm.org.uk/airmen/ShepherdFER.htm

Hurricane V6667, No. 213 Squadron
Sgt A. Wojcicki listed as missing. Shot down in Channel during combat with Bf 110s. Body never recovered.
http://www.bbm.org.uk/airmen/Wojcicki.htm

Hurricane V6665, No. 303 Squadron
F/O A. Cebrzynski died of injuries 19/9/40. Shot down during combat. Made a failed attempted crash landing.
http://www.bbm.org.uk/airmen/Cebrynski.htm

Hurricane R2682, No. 238 Squadron
Sgt S. Duszynski listed as missing. Last seen pursuing Ju 88 over Romney. Aircraft crashed at Lydd.
http://www.bbm.org.uk/airmen/Duszynski.htm

Spitfire K9793, No. 92 Squadron
P/O F.N. Hargreaves listed as missing. Failed to return after combat action. Presumed crashed into the sea.
http://www.bbm.org.uk/airmen/Hargreaves.htm

Hurricane V7240, No. 238 Squadron
Fl/Lt D.P. Hughes listed as missing. Last seen intercepting Ju 88s. Failed to return to base.
http://www.bbm.org.uk/airmen/HughesDP.htm

Spitfire N3282, No. 602 Squadron
Sgt M.H. Sprague killed. Shot down by Bf 110s over Channel. Pilots body washed ashore at Brighton 10/10/40.
http://www.bbm.org.uk/airmen/Sprague.htm

Hurricane V7242, No. 303 Squadron
Sgt S. Wojtowicz killed. Crashed and burnt out at Westerham after being shot down by Bf 109s.
http://www.bbm.org.uk/airmen/Wojtowicz.htm

Blenheim L9396, No. 235 Squadron
Believed shot down by Bf 109 during escort mission to Calais.
P/O P.C. Wickings-Smith listed as missing.
http://www.bbm.org.uk/airmen/Wickings-Smith.htm
P/O A.W.V. Green listed as missing
http://www.bbm.org.uk/airmen/GreenAWV.htm
Sgt R.D.H. Watts listed as missing.
http://www.bbm.org.uk/airmen/WattsRDH.htm

Blenheim Z5725, No. 235 Squadron
Failed to return from escort mission to Calais.
P/O N.B. Shorrocks listed as missing.
http://www.bbm.org.uk/airmen/Shorrocks.htm
F/Lt F.W. Flood listed as missing
http://www.bbm.org.uk/airmen/Flood.htm
Sgt. B.R. Sharp listed as missing.
http://www.bbm.org.uk/airmen/SharpBR.htm

Spitfire P9464, No. 92 Squadron
P/O H.D. Edwards killed. Shot down by Bf 109 during combat action and crashed into woods.
http://www.bbm.org.uk/airmen/EdwardsHD.htm

Photo Descriptions

1. The burning wreckage of Heinkel He 111H-2 ‘V4+RW’ (Wk-Nr 5364) of 6.Staffel/KG 1 at Broomhill Farm in East Guldeford, East Sussex on 11 September 1940. The aircraft was on a sortie to London Docks when it was attacked by Spitfires of Nos. 66 and 92 Squadrons, disabling both engines. All five crew members were captured.
2. The aircrew of Heinkel He 111H-3 (1H+CB) of Stab I./KG 26 are marched off by the Home Guard after making a forced landing at Burmarsh, Romney Marsh, Kent, on 11 September 1940. Their burning aircraft lies in the background.
3. Firefighters battle a gas explosion from the previous night’s air raid, Kingsway, London, 11 September 1940.
4. Messerschmitt Bf 110C-3 ‘U8+HL’ (Wk-Nr 1372) of 2.Staffel/ZG 26, shot down at 17:00 hrs on 11 September 1940. The aircraft crash-landed at Cobham Farm, Lenhem in Kent. The crew, Feldwebel Hermann Brinkmann and Unteroffizier Erwin Gruschow, were both captured.
5. Hauptmann Ernst Wiggers in the cockpit of his Bf 109E-4 ‘Black 6’. Wiggers was killed in action on 11 September, 1940.