There was no doubt that the strain, and the growing number of relatively inexperienced aircrew being committed to the battle – some with as little as 20 hours’ experience on Spitfires or Hurricanes – was beginning to tell on Fighter Command during the last days of August and into September, as the deficit between British and German losses narrowed. To make matters more difficult, the Germans were tightening up their fighter escort procedure. On 1 September, when the Heinkels of KG 1 attacked the docks at Tilbury, its 18 bombers were escorted by three Jagdgeschwader – roughly four fighters to every bomber. All the German aircraft returned to base, having been virtually unmolested by the RAF. The day’s operations cost the RAF 15 fighters, including four Hurricanes of No. 85 Squadron, against the Luftwaffe’s nine. The losses contrasted sharply with those sustained during a series of savage air battles on 31 August, when the RAF lost 24 aircraft and the Luftwaffe 28.
The scores were again close on 2 September, when several airfields, including Biggin Hill, Lympne, Detling, Eastchurch (three times), Hornchurch (twice) and Gravesend were heavily attacked, together with the aircraft factory at Rochester and Brooklands aerodrome, adjacent to the vital Hawker and Vickers factories. Fighter Command maintained standing patrols over its sector airfields during the day and lost 23 aircraft against the Luftwaffe’s 26, seven of which were Messerschmitt 110s.
On 3 September the airfield attacks continued, North Weald being very severely damaged, and in the day’s fighting the RAF and Luftwaffe each lost 16 aircraft. Meanwhile, across the Channel, events were taking a new and dramatic turn.
That morning, Reichsmarschall Göring summoned his Luftflotten commanders, Kesselring and Sperrle, to a conference at The Hague. The main item on the agenda was the feasibility of a ‘reprisal’ attack on London; the Luftwaffe Operations Staff had ordered Luftflotten 2 and 3 to prepare such an attack on 31 August, even though there still existed ab order from Adolf Hitler forbidding bombing raids on the capital.
A lack of documentary evidence makes it hard to reconstruct the process leading to the decision to attack London. Hitler’s desire for reprisals following RAF attacks on Berlin, themselves a consequence of the erroneous raid on London in August, certainly played its part, but this is not the whole of the story. Bombing attacks on targets in the London area had been at the core of a plan originated by II Fliegerkorps before the start of the air offensive, the idea being to wear down the British fighters by bringing them to battle over the city, which was within the range of German single-engined fighters. That was one valid reason for attacking the city, although it hinged on another, far less valid one. This was the belief of Luftwaffe Intelligence that Fighter Command only had between 150 and 300 aircraft left early in September, so that the final blow could be delivered to it over London. The head of Luftwaffe Intelligence, Oberst Josef Schmidt, had arrived at this conclusion by simply deducting the wildly exaggerated figures of German combat claims from the originally assumed British fighter strength, at the same time underestimating British fighter production. It was one of the most incredible misconceptions of wartime German intelligence, and yet it was supported by both Göring and Kesselring. It was not supported by Feldmarschall Hugo Sperrle of Luftflotte 3, nor by Luftwaffe Signals Intelligence, which had compiled far more accurate figures for Fighter Command’s strength.
On 4 September, Hitler declared in public that he now wanted to ‘erase’ British cities, and on the following day he gave the order to attack London and other major cities by day and night. The assault on London was to begin in the afternoon of 7 September, and was to be directed mainly against the docks. The city was to be attacked by Luftflotte 2 by day and Luftflotte 3 by night. Simultaneous attacks were to be conducted against armament factories and port installations. Thirty aircraft and armament factories were selected, and attacks on these began on 4 September, in parallel with continuing raids on Fighter Command’s airfields. But from now on, London was the key target, and on that decision rested the outcome of the Battle of Britain.
While the young pilots of Dowding’s Fighter Command fought and died over the Channel and the harvest-fields of southern England, RAF Bomber Command had been waging its own war against the enemy in the Channel and North Sea areas. On 13 July 1940, Bomber Command switched a major part of its efforts to the German invasion preparations in the ports, anchorages and harbours stretching from Delfzijl in the north of Holland to Bordeaux in south-west France. These ports were to be attacked frequently during the four years that were to pass before the Allied invasion of Europe, but the most intensive phase of the air offensive against them – the ‘battle of the Barges’, directed against the armada of small craft assembled by the Germans for the thrust across the Channel – lasted until the end of October 1940.
Aircraft of every Bomber Command Group, as well as Coastal Command and the Fleet Air Arm, took part in this nightly offensive, the importance of which has to a great extent been eclipsed by the massive air battle that dragged its vapour trails over the skies of southern England during that long summer. But the Battle of Britain was, in the broad sense, a victory for the British bombers too; for although the Hurricanes and Spitfires of Fighter Command denied the Germans the air superiority necessary for a successful invasion, the attacks mounted on the invasion ports were so effective that, even if the Luftwaffe had succeeded in obtaining temporary mastery of the air over southern England, Hitler’s invasion fleet would have been in no position to sail on the planned date.
This was clearly substantiated by the Germans themselves on several occasions. On 12 September, for example, only three days before Operation Sealion was scheduled to take place, HQ Navy Group West sent the following signal to Berlin:
Interruptions caused by the enemy air forces, long-range artillery and light naval forces have, for the first time, assumed major significance. The harbours at Ostend, Dunkirk, Calais and Boulogne cannot be used as night anchorages for shipping because of the danger of English bombing and shelling. Units of the British fleet are now able to operate almost unmolested in the Channel. Owing to these difficulties further delays are expected in the assembly of the invasion fleet.
With the invasion thought to be imminent, Bomber Command launched a maximum effort offensive against the enemy-held ports. On the night of 13/14 September the bombers sank 80 barges in Ostend harbour, and the following night severe damage was inflicted on concentrations of enemy craft at Boulogne. This raid was carried out by the Fairey Battles of the newly-formed Nos. 301 and 305 (Polish) Squadrons, flying their first operational mission. The Battles of Nos. 12, 103, 142 and 150 Squadrons – at full strength again after the losses they had suffered in France – also carried out attacks on the enemy ports during this period. It was the Battle’s swan-song as a first-line aircraft; in October it was withdrawn from operations and replaced by Wellingtons and Blenheims.
On 14 September, Hitler issued a Supreme Command Directive postponing the launch of Operation Sealion until 17 September. On the morning of the 16th, however, the German Naval War Staff once again reported that the invasion ports had been subjected to heavy bombing:
In Antwerp considerable casualties have been inflicted on transports. Five transport steamers in the port have been heavily damaged; one barge has been sunk, two cranes destroyed, an ammunition train has blown up, and several sheds are burning.
There was worse to come. On the night of 16/17 September, only hours before the crucial German Supreme Command conference that was to decide whether or not the invasion would take place, a force of Blenheims and Battles surprised a strong concentration of enemy landing craft in the open sea off Boulogne. Several barges and two transports were sunk, with heavy loss of life. The vessels had been engaged in an invasion training exercise. German bodies, washed up on the English Channel coast later, gave rise to rumours that an invasion had actually been attempted.
On that same night the RAF also struck at the whole coastal area between Antwerp and Le Havre, and this prompted the German Naval Staff to report the following day that:
The RAF are still by no means defeated; on the contrary, they are showing increasing activity in their attacks on the Channel ports and in their mounting interference with the assembly movements.
This statement was underlined by Bomber Command on the night of 17/18 September when, in full moonlight conditions, every available aircraft pounded the Channel ports and caused the worst damage so far to the invasion fleet. Eighty-four barges were sunk or damaged at Dunkirk alone, while elsewhere a large ammunition dump was blown up, a supply depot burned out and several steamers and MTBs sunk. The next day, the Naval Staff report made gloomy reading:
The very severe bombing, together with bombardment by naval guns across the Channel, makes it necessary to disperse the naval and transport vessels already concentrated on the Channel and to stop further movement of shipping to the invasion ports. Otherwise, with energetic enemy action such casualties will occur in the course of time that the execution of the operation on the scale previously envisaged will in any case be problematic.
On 19 September, four days after the great air battle over London and southern England that would henceforth be marked as Battle of Britain Day, and which cost the Luftwaffe 56 aircraft, Hitler ordered the invasion fleet assembled in the Channel ports to be dispersed so that ‘the loss of shipping space caused by enemy air attacks may be reduced to a minimum.’ Operation Sealion had been postponed indefinitely, and Hitler’s preoccupation now was with the projected attack on the Soviet Union.
Between 15 July and 21 September, according to German naval sources, the British air offensive sank or damaged 21 transports and 214 barges in the Channel ports, about 12 per cent of the total invasion fleet. These figures should be treated with some reservation, as even at this stage of the war the Germans were in the habit of playing down their actual losses in confidential reports to the Supreme Command. The actual loss, in terms of both men and material, was probably higher, but even the figure of 12 per cent is sufficient testimony that the bombing effort during those crucial weeks was far from wasted.
Nevertheless, the effectiveness of the effort against the Channel ports was grossly under-estimated by the War Cabinet. Churchill in particular expressed disappointment at the results of the attacks, as revealed by air reconnaissance, in a minute to the Air Minister, Sir Archibald Sinclair, on 23 September:
What struck me about these [reconnaissance] photographs was the apparent inability of the bombers to hit very large masses of barges. I should have thought that sticks of explosive bombs thrown along these oblongs would have wrought havoc, and it is very disappointing to see that they all remained intact and in order, with just a few apparently damaged at the entrance.
Churchill did not take into account the fact that many of the barges, although apparently intact, had been made unseaworthy by damage that the photographs did not show. The bomber crews who were over the ports night after night knew that they were sinking the barges faster than anyone had thought possible. The only question in their minds was whether they were sinking them fast enough to thwart the invasion if Fighter Command were annihilated.
The ports were easy to find, but they were not an easy target. Light flak was plentiful and losses were heavy. The anti-aircraft defences were particularly strong around Antwerp, and it was while attacking this target on the night of 15/16 September 1940, that Sergeant John Hannah, one of the crew of a Hampden of No. 83 Squadron, carried out an act of great courage that won him the Victoria Cross. The citation tells the story.
On the night of 15 September 1940, Sergeant Hannah was the wireless operator/air gunner in an aircraft engaged in a successful attack on an enemy barge concentration at Antwerp. It was then subjected to intense anti-aircraft fire and received a direct hit from a projectile of an explosive and incendiary nature, which apparently burst inside the bomb compartment. A fire started which quickly enveloped the wireless operator’s and rear gunner’s cockpits, and as both the port and starboard petrol tanks had been pierced there was a grave risk of fire spreading. Sergeant Hannah forced his way through to obtain two extinguishers and discovered that the rear gunner had had to leave the aircraft. He could have acted likewise, through the bottom escape hatch or forward through the navigator’s hatch, but remained and fought the fire for ten minutes with the extinguishers, beating the flames with his log book when these were empty.
During this time thousands of rounds of ammunition exploded in all directions and he was almost blinded by the intense heat and fumes, but had the presence of mind to obtain relief by turning on his oxygen supply. Air admitted through the large holes caused by the projectile made the bomb compartment an inferno and all the aluminium sheet metal on the floor of this airman’s cockpit was melted away, leaving only the cross bearers. Working under these conditions, which caused burns to his face and eyes, Sergeant Hannah succeeded in extinguishing the fire. He then crawled forward, ascertained that the navigator had left the aircraft, and passed the latter’s log and maps to the pilot.
This airman displayed courage, coolness and devotion to duty of the highest order and by his action in remaining and successfully extinguishing the fire under conditions of the greatest danger and difficulty, enabled the pilot to bring the aircraft to its base.
The Royal Air Force was not alone in its campaign against the German invasion forces that were assembled mainly in the ports of Dunkirk, Ostend, Calais and Boulogne. Whenever possible, even though operating conditions in the Channel had become very difficult because of air attack, the Royal Navy took the opportunity to strike at shipping movements off the enemy coast. On 8 September 1940, for example, three motor torpedo boats, MTB 14, MTB 15 and MTB 17, set out from Dover to attack a German convoy of about 30 small vessels approaching Ostend. Two of the boats, MTBs 15 and 17, entered Ostend harbour under cover of darkness and an RAF air raid and launched their torpedoes, hitting two vessels. Exactly what they hit was never established, but it was the first successful MTB torpedo attack of the war.
On the night of 10/11 September, a striking force comprising the destroyers Malcolm, Veteran and Wild Swan set out to patrol the Channel off Ostend, which was again under air attack, when radar contact was made with an enemy convoy. Soon afterwards, the destroyers made visual contact with the enemy, aided by the light of flares dropped by the RAF, and opened fire, sinking an escort vessel, two trawlers that were towing barges, and a large barge.
Offensive sweeps of this kind were a regular feature during September 1940, when the threat of invasion was at its height, the naval forces usually operating from Harwich or Portsmouth; the Dover destroyer force had been dispersed, having suffered substantial damage through air attack. At the same time, aircraft of the Fleet Air Arm, operating from bases in south-east England, joined the RAF in maintaining pressure on the enemy invasion ports.
The biggest guns the Navy could bring to bear on the enemy coast were mounted in two warships of World War I vintage, the battleship Revenge and the monitor Erebus. Both mounted 15-inch guns, the Erebus being fitted with a twin turret bearing her main armament and also with four twin 4 inch and two single 3 inch AA guns. She carried a crew of 300. On 20 September she set out from Sheerness to bombard the German gun battery at Cap Gris Nez, but the sortie had to be abandoned because of bad weather. On 30 September, however, she fired 17 rounds into a concentration of invasion craft in the Calais docks area, the fire being directed by a Fairey Swordfish spotter aircraft. On the following day, the German battery at Wissant fired precisely the same number of rounds at Dover by way of retaliation.
On 10 October it was the turn of HMS Revenge, the old battleship – armed with eight 15-inch guns – sailing from Plymouth with a screen of 5th Flotilla destroyers: Jackal, Kipling, Jupiter, Jaguar, Kashmir and Kelvin. The cruisers Newcastle and Emerald were also at sea, protecting the western flank, while a flotilla of six MTBs sailed from Portland to provide a screen against S-boats. Revenge’s target was Cherbourg, and for 18 minutes, beginning at 0333 on 11 October she laid a barrage of 120 15-inch shells across the crowded harbour, to which was added a total of 801 4.7 inch shells from the seven escorting destroyers. The resulting conflagration could be seen 40 miles (64km) out to sea. The British force reached Spithead at 0800 without damage, despite being shelled for the best part of 10 miles (16km) by a German heavy battery.
On 16 October HMS Erebus, escorted by the destroyers Garth and Walpole, again bombarded the French coast in the vicinity of Calais with the aid of spotter aircraft. Forty-five salvoes were fired, beginning at 0100, before the British force withdrew. Neither Erebus nor Revenge made any further sorties of this kind, even though the British heavy gun defences on the Channel coast in October were still pitifully weak. The pre-war heavy gun strength on the Straits of Dover, comprising two 9.2 inch and six 6 inch guns, had been reinforced during the summer by one 14 inch, two 6 inch and two 4 inch guns, all Naval weapons, together with a pair of 9.2 inch guns on railway mountings; and in October these were further reinforced by two 18.5 inch guns from the old depot ship Iron Duke, also on railway mountings, and a battery of four 5.5 inch guns from HMS Hood. Further heavy gun batteries, at Fan Bay, South Foreland and Wanstone, would not become operational until a much later date, by which time the invasion threat had passed.
While the British strove to disrupt enemy invasion plans, German destroyers were extremely active in the Channel area during September and October 1940, laying minefields to protect the flanks of their projected cross-Channel invasion routes and also making hit-and-run sorties against British shipping. One particularly successful sortie was undertaken on the night of 11/12 October by the German 5th Flotilla from Cherbourg, comprising the destroyers Greif, Kondor, Falke, Seeadler and Wolf. They sank the armed trawlers Listrac and Warwick Deeping with gunfire and torpedoes, and shortly afterwards destroyed the Free French submarine chasers CH6 and CH7, manned by mixed French and Polish crews. The German ships withdrew safely; although they were engaged by the British destroyers Jackal, Jaguar, Jupiter, Kelvin and Kipling, the latter achieved nothing more spectacular than several near misses. Another inconclusive action was fought between British destroyers of the 5th Flotilla, supported by the light cruisers Newcastle and Emerald, and enemy destroyers off Brest on 17 October, with no damage suffered by either side. The British warships came under air attack during the operation, the most serious threat coming from a flight of very determined RAF Blenheims whose crews had clearly not been trained in warship recognition!
November 1940 saw a resurgence of air attacks on British shipping by Junkers Ju 87 Stukas, which had been standing by at their airfields in the Pas de Calais to lend tactical support to Operation Sealion, now postponed. Their area of operations was the Thames estuary, where British convoys were assembling, and between 1 and 11 November they sank one merchant vessel and damaged six more. On 14 November they attacked targets in the Dover area, destroying a drifter and damaging three more vessels, but these missions marked the Stuka’s swansong over the British Isles.
There was a further destroyer action on 27/28 November 1940, when the British 5th Destroyer Flotilla intercepted an enemy flotilla from Brest. In the ensuing engagement the destroyer HMS Javelin was hit by two torpedoes, which blew off her bows and stern and detonated the ammunition in her magazine, destroying her superstructure as well as killing three officers and 43 ratings. Amazingly, she remained afloat and was towed into harbour, to spend 13 months in dock being virtually rebuilt. She eventually returned to operations and went on to survive the war.
Notwithstanding actions such as these, it was enemy mines that accounted for the highest proportion of British shipping losses in the closing months of 1940. Of the 42 Royal Navy vessels lost in the Channel area between 1 September 1940 and the end of the year, 28 were sunk by mines.
The threat of invasion had receded, and Hitler’s eyes, by the end of 1940, were turned towards the east. But the question must be asked whether Operation Sealion might have succeeded, had it gone ahead. All the accumulated evidence suggests that it would not. The matter is summed up admirably by the official Royal Navy historian:
We who lived through those anxious days may reasonably regret that the expedition never sailed for, had it done so, it is virtually certain that it would have resulted in a British victory comparable for its decisiveness to Barfleur or Quiberon Bay; and it can hardly be doubted that such a victory would have altered the entire course of the war. It is indeed plain today that, of all the factors which contributed to the failure of Hitler’s grandiose invasion plans, none was greater than the lack of adequate instruments of sea power and of a proper understanding of their use on the German side. Britain, on the other hand, not only possessed the necessary ships and craft, but they were manned by devoted crews who were imbued with a traditional and burning desire to come to grips with the enemy invasion fleet. Finally, we may remark how the events of the summer of 1940 emphasised once again what many other would-be conquerors of Britain had learnt in turn – namely, that an overseas expedition cannot be launched with any prospect of success without first defeating the other side’s maritime forces, and so gaining control of the waters across which the expedition has to pass.
In conflict with a centuries-old maritime power, there is little doubt that Hitler, had he launched his invasion, would have learnt too late the landsman’s lesson.