Air War over the Netherlands 1940

“Mower On the Prowl”
This is a depiction of the Fokker G.I.a 312 flown by P. Noomen with H. de Vries as gunner. It started as first G.I.a during the bombardment of Waalhaven (Rotterdam) airbase on the 10th of May, 1940. After shooting down 2 Heinkel 111s it landed back at Waalhaven with a punctured fuel tank and the right engine stopped. The closest Heinkel is 5J+DA, of stab KG4, which belly landed in St. Annapolder with one crew member killed. The geschwaderkommodore Oberst Fiebig and crew were captured unhurt. Wiek Luijken

The Dutch were relying on the natural obstacles provided by the Zuiderzee in the north and the numerous waterways at the mouth of the Maas in the south. In the west, the main defensive position was the Grebbe Line running along the Geld Valley. Behind that was a fallback position running from just east of Amsterdam to the east of Rotterdam. Both lines took maximum advantage of low-lying land that could be flooded. South of the Maas, the Peel marshes were only lightly held. The Dutch had chosen the shortest and easiest lines to defend. The disadvantage was that their main southern defences ran parallel to the Belgian northern Albert Canal defences, leaving a corridor between for the Germans to advance through.

The German High Command hoped to eliminate Holland on the very first day by landing troops inside ‘Fortress Holland’. Airborne troops were to capture three airfields (Ypenburg, Ockenburg and Valkenburg) around The Hague, from where they would push into the city and capture the Dutch Royal family. If this failed, paratroopers dropped on the Moerdijk, Dordrecht, and the Willemsbrug bridges and Waalhaven Airfield would clear a path for the 9th Panzer Division racing through southern Holland.

The German forces that landed in and around The Hague were soon in trouble. Many of the Ju 52 transports were either shot down, destroyed by obstacles erected on the airfields, or simply found the Dutch airfields were unable to support their weight. The damaged and wrecked planes that littered the airstrips prevented the follow-up waves from landing. Many had to force land on any nearby flat land they could find. The surviving German troops were soon fighting for their lives. Forty ground-attack sorties flown by Dutch fighters and light bombers supported the Dutch counterattacks. Further east, Dutch forces withdrew in fairly good order to the Grebbe Line. In the south, Panzers and the Ju 87 dive-bombers of Fliegerkorps VIII, the Luftwaffe’s short-range close-support force, had little difficulty blasting their way through the weakly held Peel Marsh defences.

As soon as the attack was underway, the air attaché informed the Dutch Army commander about the RAF plans to bomb advancing German columns, provided their location could be established. At 7.30 a.m., the Dutch told the air attaché that the German forces landing at Waalhaven were the most serious threat and asked for the airfield to be bombed. The message was passed on to London. When no attack came, the air attaché was bombarded with calls emphasising how critical the situation was becoming and demanding to know what was holding up the RAF.

The message certainly got through to Newall. Armed with the information provided by the air attaché, Newall told the morning cabinet meeting that the Dutch had matters in hand around The Hague, but Waalhaven was a problem and six fighter Blenheims were being sent to strafe the airfield. Newall explained that he had decided not to use bombers because of the risk of civilian casualties. In fact, Dutch aircraft were already bombing their own airfields. The six Blenheims were in fact the only Air Ministry attempt to implement the fighter support the Air Ministry had promised. Their primary mission was to shoot down enemy aircraft and only strafe the airfield if none were encountered.

By midday, requests were coming from Barratt in France for Bomber Command to intervene in the Netherlands. The missions subsequently flown appear to have been based on information gathered by reconnaissance planes rather than as a response to requests from The Hague. Twenty-four Blenheims attacked German forces in The Hague region, where, as Newall had explained to the cabinet, the Dutch felt they were in reasonable control. Twelve of the planes bombed Ypenberg Airfield after it had been recaptured by the Dutch. Early in the afternoon, nine Blenheims bombed Waalhaven. This was the only RAF bombing attack on the airfield that day, and even this appears to have been a response to Barratt’s demand for some action rather than the Dutch pleas via the air attaché. Three of the thirty-one Blenheim bombers were lost—ironically, two of them shot down as they attacked the recaptured Ypenburg Airfield. The Blenheim fighters operating over Waalhaven did not fare so well. The original plans for protecting Dutch airfields had proposed using Spitfires or Hurricanes where possible—using Blenheims would be risky. So it proved. Five of the six Blenheims were shot down by Bf 110s.

The next planned Bomber Command support for the Dutch was to be the attack on the Ruhr. The Air Ministry was expecting the government to give the go-ahead for the operation that night. The desperate appeals to do something about the growing strength of the German forces holding Waalhaven seemed to be falling on deaf ears.

By the end of the day, Dutch counterattacks had recaptured all the occupied airfields except for Waalhaven. Fortunately for the Dutch, the British Government did not authorise the Ruhr operation. A frustrated Portal ordered the Wellingtons of No. 3 Group to attack Waalhaven instead. The Dutch lit a bonfire to guide the bombers in, and thirty-six Wellingtons kept up a steady bombardment throughout the night. Flying at little more than 2,000 feet, the Wellingtons dropped 58 tons of bombs on the beleaguered German forces. The Dutch were delighted, and at 5 a.m. they requested a halt to the bombardment so that they could launch their next counterattack. Less appreciated or indeed even noticed were the nine sorties flown by the two Whitley squadrons against bridges just over the Dutch border, in German territory.

On the morning of the 11th, the Dutch attempt to retake the airfield failed. The RAF was asked to resume their bombardment while the few remaining serviceable Dutch planes focused their efforts on the German troops still holding both ends of the nearby Willemsbrug bridge. The aim at this stage was not to destroy any of the captured bridges. The Dutch wanted them intact so that the advancing French could use them to reinforce Fortress Holland. In the morning, and again in the afternoon, the two surviving Fokker T.V bombers, flying low and escorted by Fokker D.21s, scattered 50-kg bombs on the German troops around the bridge. The RAF attacks on the airfield, however, did not materialise; indeed, the air attaché was informed that there would be no more attacks. No reason was given. At around midday, an embarrassed air attaché told the Air Ministry the Dutch were ‘seriously upset’ by the decision and were pleading for it to be reconsidered. A succession of Dutch Army officers turned up at the embassy to emphasise the huge importance of eliminating the besieged German forces holding Waalhaven. The Dutch ambassador in London was told to try and speak to Churchill in person.

On the 11th, Fighter Command was more active over southern Holland. Crowds cheered as Hurricanes patrolled The Hague. However, a patrol by twelve Hurricanes of No. 56 Squadron in The Hague-Rotterdam area ended in disaster when the formation was surprised by Bf 109s and five were shot down. The next day, two out of a flight of three Blenheims were lost. A flight of three Spitfires was caught by Bf 109s, losing one of their number.

For many of the British-based pilots, this was their first experience of combat. The circumstances could not have been more demanding. They were not trained in fighter-versus-fighter combat, and they were confronted by confident, experienced Luftwaffe fighter pilots. They were operating in small numbers—often lone flights of six, sometimes just sections of three—so they were invariably outnumbered. Operating in these circumstances, so far from their home bases, was not the ideal way to gain combat experience.

Something had to be done about the way British fighters were being taken by surprise and picked off by the high-flying German Messerschmitts. Instead of changing the tight vic  formations that were largely responsible for the problem, Defiants were assigned the task of covering the rear. It was a chance to test the theory that the turret fighter could be used to establish air superiority in skies dominated by the enemy. The composite Defiant/Spitfire formation had its first real test on the 13th. The formation was engaging Ju 87 dive-bombers west of Rotterdam when it was bounced by the German escort. The German pilots might well have mistaken the Defiants for defenceless single-seaters and been surprised by the defensive fire that greeted them, but their surprise was short-lived; five of the clumsy Defiants and a Spitfire were shot down for the loss of just one Messerschmitt. It seemed fairly conclusive proof that Dowding had been right—using the Defiant offensively could be no more successful than Trenchard’s offensive F.E.2 patrols of the First World War. However, the advocates of the turret fighter were still not convinced. The Defiants had claimed four Ju 87s before the German fighters intervened, and this was enough to ensure the experiment continued—once the battered Defiant squadron had recovered.

On the ground, the situation in the south of the Netherlands was already becoming critical. On the 11th, forward elements of the French 7th Army approaching Breda were brushed aside by the 9th Panzer and its supporting Ju 87 dive bombers. The French instinctively sought sanctuary in a safe defensive line and lost all interest in helping recapture the Moerdijk Bridge. General Winkelman, the Dutch Army commander, now realised that there was little likelihood of any help from the French; the only hope was to try and destroy the captured bridges to the south of the city and hang on in Fortress Holland. The Grebbe Line was just about holding. The main Dutch concern was still the German forces clinging on to their foothold inside Fortress Holland, around the Willemsbrug Bridge and nearby Waalhaven. The air attaché in The Hague was still furiously relaying Dutch appeals for air support to the Air Ministry, but getting no response. In desperation, the Dutch asked the military attaché at the embassy to pass on a message via the War Office, begging ‘most earnestly’ that Waalhaven be bombed. The only response came from the Navy; while Portal’s bombers waited for permission to bomb the Ruhr, at dusk on the 12th, six Coastal Command Beauforts and nine Fleet Air Arm Swordfish attacked the airfield. By this time, the 9th Panzer Division had reached the German paratroopers holding the Willemsbrug Bridge.

The Dutch did the best with their own dwindling air resources. After flying most of its ground-attack missions on the 10th without fighter escort, for the remainder of the campaign the Dutch Air Force provided their low-level bombers with close escorts. This put the fighters at a tactical disadvantage, but it did mean they could actually help the bombers if they encountered enemy fighters. If no enemy fighters were around, they were in a good position to join in the attack. Anthony Fokker had lost none of his flair for designing fighters; the Fokker D.21, with its fixed undercarriage, might have lacked the speed of more modern fighters, but its superb handling and agility gave the Dutch pilots a fighting chance. With an escort, the hedgehopping Fokker C.V and C.X biplanes managed to deliver their attacks without incurring the crippling losses suffered by the Battle squadrons.

On the third day of the invasion, the Dutch Air Force was engaged all along the front. Operating from emergency airstrips away from their main airfields, ground-attack missions were flown against German forces threatening the defences that secured the northern end of the dyke at the mouth of the Zuiderzee. Retreating remnants from The Hague landings, trying to fight their way south to Rotterdam, were also targeted. Waalhaven was bombed. Troop columns and artillery positions around the Wageningen sector of the Grebbe Line, where the Dutch defences were under particular pressure, were also attacked. The numbers were tiny—the largest operation was just seven Fokker C.Xs with six Fokker D.21s escorting. The smallest was a lone Fokker T.V with a single D.21 escort. The attacks may not have been devastatingly effective, but they were at least in the areas the Dutch Army needed them. Just the sight of their own planes roaring in at low level raised the spirits of the Dutch troops.

By the evening of the 12th, German troops had achieved a shallow penetration of the Dutch defences in the Wageningen sector, forcing the Dutch back to their last line of defence. The Grebbe Line was in danger of collapsing. The Dutch Defence Minister personally asked for the RAF to bomb the Moerdijk Bridge (to halt the advance from the south) and the roads leading to Wageningen (to slow down the German advance from the east). He was told the bridge was far too solid to be destroyed by air attack, which was true, and that attacks on roads could only bring temporary relief. This was also true, but that was what was all the Dutch wanted. No. 2 Group in East Anglia could not help, but, rather bizarrely, the Dutch request was passed on to Barratt in France to see if his Battle squadrons south of Reims could lend any support.

Dutch frustration was growing. The Air Ministry had refused Dutch pleas to base RAF squadrons in the Netherlands. Could they at least use Dutch airstrips to refuel, as French aircraft were doing? The Air Ministry came up with all sorts of reasons why this was impossible: Dutch fuel hoses were the wrong size; British planes needed different fuel. In truth, if the Air Staff and Dowding were reluctant to send fighters to France to support the British Army, they were hardly likely to send them to the Netherlands to support the Dutch Army. The Dutch were told that there were always more crucial battles elsewhere and the RAF was needed there. This was true, but it was not true that the RAF was fully engaged in these crucial battles. Most of the Wellington, Hampden, and Whitley squadrons were just sitting on their airfields, waiting for the offensive against the Ruhr to start. Two-thirds of RAF fighter squadrons were waiting for the German bombers to come.

Dutch pleas now became ultimatums. The Dutch Foreign Minister spelt it out—first to members of the Air Staff, and then to Ismay, Churchill’s military advisor. Either the British provided air support or the Dutch government would have to consider surrendering. No assurances were forthcoming, and the Dutch government and Royal Family prepared to leave the country. Winkelman was given full authority to cease fighting if he judged the military situation had become hopeless.

Far from stepping up its efforts, Fighter Command was reducing the scale of its operations. Too many fighters had already been lost. Cover was provided for the evacuation of British citizens from Ostend and the Dutch Royal Family and government from The Hague, but there was nothing in the key battlezone. Early on the morning of the 13th, the last Fokker T.V, escorted by two Fokker G.1s, set off for the Moerdijk Bridge with 300-kg bombs. The damage these large bombs could inflict on the huge structure was never put to the test; only one hit the bridge, and it failed to explode.

On the Grebbe Line, a Dutch counterattack on the morning of the 13th on the Wageningen sector was defeated by heavy German artillery and Luftwaffe air support. A withdrawal to the final ‘Fortress Holland’ line became the only option. With the Luftwaffe dominating the skies, this was not possible until the sun had set. It would be a desperately difficult day for the Dutch Army. Low cloud provided some respite from German air strikes, and despite the weather, the Dutch Air Force was still flying and provided as much support as possible. Around twenty Fokker D.21s, C.Xs, and G.1s strafed and bombed German artillery positions and troops in the Wageningen area. Yet another plea to the British Embassy revealed the staff had joined the exodus to Britain. Despite the problems, during the following night the Dutch forces successfully withdrew along the entire front to their last line of defence.

On the morning of the 14th, the situation looked relatively stable. The Dutch forces were well-established in Rotterdam; the German forces holding the northern end of the bridge could not be dislodged, but Dutch guns were preventing any movement across the waterway. In the east of the country, the Germans were only slowly following up the Dutch withdrawal from the Grebbe Line. Hitler, frustrated by the slow progress, ordered an intensification of effort on all fronts. An assault on Rotterdam would be preceded by the bombing of the Dutch Army positions on the north bank. The target area would stretch as far as the city centre. The Dutch were warned an air attack was on the way and given one last chance to surrender.

Winkelman was not convinced there was any immediate need to surrender. The Dutch were certainly in no hurry to come to a decision—there was no reason to fear this particular German bomber threat more than previous bombing. The German Air Force had been bombing the country for four days. A second deadline was approaching and the negotiations were still in progress. Ninety He 111s of KG/54 were already heading for Rotterdam. The German commander tried to delay the attack, but only half the force saw the warning red Very lights. Fifty-four Heinkel bombers dropped 97 tons of bombs on the designated target area. There was no anti-aircraft defence, and the last serviceable Dutch fighters, five Fokker D.21s and five G.1s, were further north, providing cover for the troops still pulling back from the Grebbe Line. The Heinkels were able to drop their bombs with precision from 2,000 feet.

Unopposed bombing from low level can be particularly destructive. Even so, nobody anticipated what was about to happen. The bombs were high-explosive rather than incendiary, but the target area contained warehouses full of inflammable produce. These were among the first buildings to be hit, and flames soon engulfed the wooden houses of the historic city centre. One square mile of the city was devastated; 800 people lost their lives. Winkelman was severely shaken by the scale of the destruction. The German commanders on the spot were just as stunned. The German propaganda machine was quick to exploit the situation. If the Dutch did not surrender, a similar fate would befall Utrecht, which was also now in the front line. Winkelman ordered all Dutch forces on the mainland to lay down their arms.

At the time, the death toll in Rotterdam was put as high as 30,000. It seemed the prophets of doom had been right; bombing alone could bring a country to its knees. Whether the same decision would have been made if the bombing had occurred on 10 May, with Allies apparently coming to Holland’s aid, is open to question. By the time the attack was launched on the 14th, the Dutch government had in principle already taken the decision to surrender. Nevertheless, for the Air Staff it was conclusive proof of how destructive and decisive bombers could be and a reminder of why Britain had to keep fighters back to defend British cities.

Lack of British support was not the only reason for the Dutch defeat, nor even the main one. The French reluctance and inability to engage the Panzers in mobile warfare around Breda was at least as significant. Nevertheless, the Dutch might have reasonably expected more support from a major military power like Britain. Given the importance attached to preventing the Netherlands from falling into German hands, Britain might have been expected to provide it. Not even the fear of invasion or heavier bombing raids on London, or the advantage of having friendly territory on the approach to the Ruhr, could induce the Air Staff to use the RAF as Dutch Army commanders wanted.

Another useful ally had been lost to the Allied cause. It was one thing to allow Poland, a valiant ally on the other side of Europe, to be overwhelmed by a powerful neighbour, or indeed Norway, a nation many hundreds of miles from our shores. It was quite another matter to allow a similar fate to befall an equally valiant ally just the other side of the North Sea. Britain could not afford to lose allies so easily.

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