'Neptune' (iv) was the British crossing of the Seine river at Vernon in northern France by Major General G. I. Thomas’s 43^rd Division (25/28 August 1944).

This division spearheaded the advance of Lieutenant General B. G. Horrocks’s XXX Corps of Lieutenant General Sir Miles Dempsey’s 2^nd Army within General (from 1 September Field Marshal) Sir Bernard Montgomery’s Allied 21^st Army Group over the Seine river, leading to a rapid advance via Amiens, Arras and Tournai to Brussels, the Belgian capital, which was reached on 3 September.

As the Allied forces streamed out to the east after the defeat of SS-Oberstgruppenführer und Generaloberst der Waffen-SS Paul Hausser’s (from 23 August General Hans Freiherr von Funck’s, from 24 August General Heinrich Eberbach’s and from 30 August General Erich Brandenberger’s) 7^th Army in the Falaise 'pocket' from 16 August, their immediate objective was the liberation of Paris and the seizure of bridgeheads on the eastern side of the Seine river running basically south-east/north-west through Paris to the English Channel at Le Havre. In the short term Dempsey could not effectively deploy his forces until General H. D. G. Crerar’s Canadian 1^st Army on his left moved onto a more north-easterly axis and Lieutenant General Omar N. Bradley’s US 12^th Army Group on his right gave his army the room to do so: moreover, the 2^nd Army would soon meet the formations of Major General Charles H. Corlett’s XIX Corps and Major General Wade H. Haislip’s XV Corps of Lieutenant General Courtney H. Hodge’s US 1^st Army wheeling to the left at right angles across his front to move in the direction of Rouen as ordered by General Dwight D. Eisenhower, the Allied commander-in-chief.

This crisscrossing of formation boundaries entailed complex command arrangements, and inevitably affected the Allied air forces. For the time being it was arranged that Nos 83 and 84 Groups of Air Vice Marshal Sir Arthur Coningham’s British 2^nd Tactical Air Force would operate only as far forward as the Risle river, and Lieutenant General Lewis H. Brereton’s (from 7 August Major General Hoyt S. Vandenberg’s) US 9^th AAF between the Risle and Seine rivers. As it happened, however, the bad weather which had started on 20 August lasted for four days and limited flying.

The 21^st Army Group’s two armies were to advance to the Seine river on a front of four corps, Lieutenant General Sir Richard O’Connor’s VIII Corps being left near Vire in army group reserve and its transport added to the general pool available to the other four corps. Dempsey allocated the task of forming his 2^nd Army’s and the 21^st Army Group’s southern formation to the XXX Corps, and ordered it to secure the 2^nd Army’s southern crossing of the Seine river at Vernon while Lieutenant General N. M. Ritchie’s XII Corps had first to wait for the Canadian 1^st Army to clear its front and then move up on the left of the XXX Corps and cross the Seine river near Louviers. The Canadian 1^st Army was sending Lieutenant General G. G. Simonds’s Canadian II Corps through Vimoutiers and Bernay to reach the Seine river at Elbeuf and Lieutenant General J. T. Crocker’s British I Corps to the Risle river at Pont Audemer.

It was the 21^st Army Group’s plan from this time onward that any German garrisons which resisted in the towns along the southern side of the English Channel were not to be attacked directly but instead isolated and bypassed as economically as possible.

As the leading formations of the US XIX Corps moved to the north from Verneuil, the XXX Corps started to the east from the area of Chambois. Its 11^th Armoured Division, under the command of Major General G. P. B. Roberts, reached the Touques river near Gace on the evening of 21 August. Here the division outflanked modest German resistance and reached Laigle during the next day. On 23 August the XXX Corps was able to deploy a second division and this quickly cleared the large Forêt de Breteuil lying just to the east of the Risle river. By 24 August the corps' third formation, the 43^rd Division, which Horrocks had instructed to cross the Seine river at Vernon and held in reserve while it made its preparations, started to move forward. Just ahead was the left flank of the US 1^st Army, and approaching its left flank was the XII Corps which, as had been anticipated, had had to wait for the Canadian 1^st Army to move before itself starting to advance. It had to lose Major General L. O. Lyne’s 59^th Division, which had been selected for disbandment to provide reinforcements for other divisions, but received Major General C. M. Barber’s 15^th Division, which was to seize the corps bridgehead near Louviers. By 24 August the corps was well on its way and the armoured cars of its reconnaissance elements would soon meet US patrols on the Risle river south-east of Bernay. By the evening of the same day the Canadian II Corps had reached Bernay as it headed toward Elbeuf, and during the following day all three Canadian divisions crossed the Risle river and, near Elbeuf, met the US forces which, with the arrival of the Canadians, cleared the place during that night and then prepared to withdraw.

At the same time the I Corps had continued its advance near the coast, crossing the Touques river on 22 August and taking Pont l’Evêque and Deauville on the same day. Two days later Lisieux fell and the rest of the corps closed to the Risle river. By a time early in the morning of 26 August, the I Corps held the line of the Risle river, between Montfort and the sea, including Pont Audemer where Major General R. N. Gale’s 6^th Airborne Division completed its final undertaking of the 'Overlord' campaign.

During this last week the US forces which had turned to the north across the British front had done well. The armoured spearheads of the XIX Corps, driving north from Verneuil and Dreux, had easily scattered the infantry detachments of General Adolf Kuntzen’s LXXXI Corps trying with minimal hope of success to halt the armour-rich US formations in good tank country. The US advanced guards, thrusting through Evreux, were in fact almost at Elbeuf as the Canadians approached. Thereabouts they ran into more stubborn resistance from various groups of armour collected by SS-Oberstgruppenführer und Generaloberst der Waffen-SS Josef Dietrich of the 5^th Panzerarmee and SS-Obergruppenführer und General der Waffen-SS Georg Keppler’s I SS Panzerkorps 'Leibstandarte' in an attempt to re-create a German defensive line.

Farther to the east, between the Eure and Seine rivers, the broken and wooded country lent itself to ambushes and delaying tactics. There the XV Corps shattered a number of Panzergrenadier Kampfgruppen, and approached Louviers on 24 August. Though the 5^th Panzerarmee and 7^th Army had moved thousands of vehicles across the Seine river between 20 August and the evening of 24 August, the period in which the weather had been too poor for flying, the US thrusts had now deprived them of more than half the ferries they had been using, and consequently the two big loops made by the Seine to the south and south-west of Rouen became packed with transport.

It was at this stage that the XV Corps was ordered to withdraw, leaving the XIX Corps to complete its tasks on 25 August. The XIX Corps thus secured both Louviers and Elbeuf.

While the British and Canadian formations were advancing to the Seine river, preparations were being completed for the rapid bridging of this water barrier. From Rouen to the sea the river widens and is subject to strong tides, and the French had never attempted to bridge the river in these lower reaches. Between Rouen and Paris the river is some 250 yards (230 m) wide, or indeed wider, and all the bridges had been sundered by air attacks. The river is littered with many small islands, and winds between steep cliffs on one side and long, low approaches on the other. As far upstream as Louviers the Seine river is a tidal water way, and subject to sudden bores or tide waves.

The Allies felt that while bridgeheads would probably be won with comparative ease, they would face altogether more difficult task in constructing the new crossings needed for the adequate maintenance of large forces. The available engineer troops and equipment of the 21^st Army Group were divided between the XXX Corps, XII Corps and Canadian II Corps so that each corps had 21 field companies. In the XXX Corps, the 43^rd Division, tasked with crossing at Vernon, was structured in three groups. The first, with the troops and equipment for bridging the Eure river and assaulting the Seine river, contained 1,500 vehicles. The second, with most of the artillery and the material for one bridge, had 1,900 vehicles. The third, with the rest of the division, had about 1,000 vehicles.

The leading group harboured in the Forêt de Breteuil during the night of 24/25 August, and sent forward its reconnaissance elements, together with some engineers, to repair the bridge over the Eure river at Pacy. Two four-hour timings along only a single route through the XIX Corps area were allocated to the division for 25 August. By 16.00 the first group had assembled to the west of Vernon for an assault during the evening. The second group was too large for its allotted timing, however, and about 700 vehicles had to be filtered through the US columns during the night.

On 26 August the XIX Corps began to withdraw to the south and the XXX Corps, moving to the east, was given one six-hour period to pass through the US formation in the morning on two routes. But again this was insufficient for Major General D. A. H. Graham’s 50^th Division and also for the 43^rd Division’s last group, which reached the river only late in that night. The XXX Corps had another six-hour timing on 27 August, and then the US forces were finally clear of the British sector early in the next morning.

Being a little later in arriving on the scene, the XII Corps suffered few difficulties of this nature. The 15^th Division’s commander planned to assault on 27 August. The Canadian II Corps would also be ready to launch two divisions to the east of Elbeuf early on the same day. To the north of the town the situation was different, however, for between the Forêt de la Londe and the mouth of the Seine river stood the final elements of the 5^th Panzerarmee, with defensive lines across the three loops of the Seine river marked by Rouen, Duclair and Caudebec en Caux. These had still to be cleared, the first by Major General C. Foulkes’s Canadian 2^nd Division and the other two by the I Corps.

During the morning of 25 August the weather improved and fighters of the 2^nd Tactical Air Force began a day of ceaseless attacks on Seine river traffic and German vehicles collecting on the waterway’s left bank. The great havoc which was wrought culminated in an attack on a German convoy observed by reconnaissance aircraft early in the evening. A number of medium bombers of Air Vice Marshal B. E. Embry’s No. 2 Group, on their way to the Seine river, were retasked while in the air, and 30 of them attacked. The Germans reported that they were unable to complete a new floating bridge at Rouen and that ferries farther downstream at both Caudebec and Quillebeuf had been destroyed by direct hits. On the same day the 9^th AAF prevented German aircraft from making an all-out effort to cover the Seine river and the remaining ferries. A large number of German aircraft were caught over Beauvais and Soissons, and at their new bases to the east of Paris, and many were destroyed. The record of Generaloberst Otto Dessloch’s Luftflotte III for the day reveals the loss of 78 aircraft. Similar operations by both tactical air forces continued throughout 26 August in the face of intense German Flak round Rouen, resulting in a large number of Allied losses.

On 26 August Montgomery issued a new directive. So far as the 21^st Army Group was concerned, the intention was now to 'destroy all enemy forces in the Pas de Calais and Flanders, and to capture Antwerp'. After crossing the Seine river, the Canadian 1^st Army was to take Dieppe and Le Havre with the minimum forces and quickly clear the coastal belt as far as Bruges. Brereton’s Allied 1^st Airborne Army would be dropped in the Pas de Calais well ahead of the Canadian columns, which should operate with their main weight on the right and deal with resistance by outflanking movements. The 2^nd Army was to cross the Seine river with all speed and, ignoring the situation on its flanks, secure the area Amiens, St Pol and Arras, with a strong armoured force making a dash for Amiens. Swift and relentless action by the 2^nd Army would thus sever the lines of communications required by the German forces facing the Canadian 1^st Army. With these objectives achieved, the 2^nd Army must be ready to drive forward through north-eastern France and into Belgium.

Montgomery had arranged with Bradley that the boundary between the two commanders' army groups should run generally on the line between Mantes and Antwerp via Gassicourt, Beauvais, Albert and Douai.

The 12^th Army Group had been ordered 'to thrust forward on its left, its principal offensive mission being, for the present, to support Twenty-First Army Group in the attainment of [its] objectives'.

Montgomery considered that the Germans lacked the strength to hold any strong position. Speed of action and movement was now vital.

On 25 August the guns and mortars of the XXX Corps opened fire on the German positions across the Seine river from Vernon. Some 15 minutes the guns changed to smoke shell, and the first British troops began to cross the river in storm boats as the road bridge which joined Vernon to Vernonnet on the opposite bank had been severely damaged and the railway bridge some 400 yards (365 m) downstream had a large section missing. On the right the two leading boats grounded on a submerged island, they and most of the embarked men being destroyed by German fire from the eastern bank. Other boats turned upstream and landed about half a company of infantry, but seven of the eight boats that had started originally had by then been lost and further crossings there were postponed till after dark. Two companies of the left-hand battalion had been landed on what also proved to be an island but were re-embarked and crossed near by.

Despite these problems, one and a half battalions crossed the river during the night, fighting off a number of German attacks and destroying troublesome mortar and machine gun posts. Sappers were meanwhile busy bridging the river, though held up for a time by German fire.

Meanwhile Vernonnet had been cleared, and by a time late in the afternoon of 26 August a light bridge had been completed and armoured cars, carriers and anti-tank guns were also being rafted across. Infantry pushed out to the high ground beyond Vernonnet, and the 43^rd Division’s second brigade began moving to strengthen and enlarge the bridgehead. Some tanks of Brigadier G. E. Prior-Palmer’s 8^th Armoured Brigade were ferried across early on 27 August and helped to counter determined efforts by infantry and some PzKpfw VI Tiger heavy tanks, rushed up from Beauvais in an attempt to destroy the bridgehead. After stiff fighting all the Germans attacks were repulsed, and during the evening of the same day the division’s third brigade began crossing. On the next day the division and its attached troops drove through the large Forêt de Vernon and established a perimeter 4 miles (6.4 km) to the east of the Seine river.

Completion of its task had cost the division some 550 casualties, but the formation had also taken about the same number of prisoners as well as inflicting on the Germans large numbers of dead and wounded.

Meanwhile other formations of the XXX Corps were moving forward to press the advance: the 11^th Armoured Division was crossing the river, and from Condé, some 120 miles (195 km) to the rear, Major General A. H. S. Adair’s Guards Armoured Division was moving forward with its tank transporters and expected to reach the river on 29 August. The XII Corps, on the XXX Corps' left, had also won bridgeheads on the eastern side of the Seine river by 27 August. One brigade of the 15^th Division had crossed in storm boats followed by DUKW amphibious trucks near St Pierre du Vauvray, about 2 miles (3.2 km) from Louviers, and a second near Portejoie, a few miles farther downstream, where little opposition was met. By 11.00 on 28 August the two bridgeheads had been joined and extended to the east, making it possible for the division’s third brigade to cross unmolested at Muids, below Les Andelys. Engineers had been hard at work rafting carriers and anti-tank guns across and bridging the river, and before midnight on 28 August a light bridge was open for traffic at Muids and a heavier bridge for tanks at St Pierre. By 29 August Les Andelys had been included in the bridgehead, men of the 15^th Division were holding the high ground above it, and patrols were in touch with the 43^rd Division on the right. Major General R. K. Ross’s 53^rd Division and Brigadier R. M. P. Carver’s 4^th Armoured Brigade were preparing to pass through the 15^th Division’s bridgehead. Major General G. L. Verney’s 7^th Armoured Division was moving across from the I Corps, but was still some 30 miles (48 km) from Louviers.

The Canadian 1^st Army, and especially its II Corps at Elbeuf, to the south of Rouen, had faced a more difficult task inasmuch as the remnants of the 5^th Panzerarmee to the west of the Seine river were crowded ahead of them in a bridgehead formed by the Rouen, Duclair and Caudebec loops of the river, and were holding the Forêt de la Londe to the north-west of Elbeuf, which covered most of the Germans' remaining escape routes.

As a result of the use of large quantities of bridging material to cross the Touques and Risle rivers, and some delay in the arrival of what was needed at the Seine river, the crossing could not begin till the morning of 27 August, though on the night before a few men of Major General H. W. Foster’s Canadian 4^th Armoured Division had crossed the Seine river in a small boat about 3 miles (4.8 km) above Elbeuf and established a small bridgehead. In the morning infantry of the division crossed in storm boats at that point, and men of Major General D. C. Spry’s Canadian 3^rd Division had also at Elbeuf, meeting little opposition.

Ahead of the Canadian division, however was Generalleutnant Hans-Kurt Höcker’s 17^th Felddivision (L) holding the high ground with the task of blocking approaches to Rouen from that side of the river. The infantry became involved in heavy fighting so the Canadian 4^th Armoured Division moved its armoured brigade to the other bridgehead at Elbeuf, where the engineers had tank-carrying rafts in operation by midnight. Early on 28 August a Bailey pontoon bridge was also open there, and by the fall of night the two divisions were strongly established on the low hills north of Igoville.

On 29 August the Canadian advance continued. From the bridgehead to the east of the Seine river, the Canadian armour reached Boos and, nearer the river, the infantry reached positions within 5 miles (8 km) of Rouen. To the west of the Seine river, in the Forêt de la Londe, a fresh German division from the Pas de Calais area, a number of extemporised Kampfgruppen and some armour had been ordered to hold their positions whatever the circumstances. Despite attacks by 500 light and medium bombers on the crossings behind them, the Germans fought a skilful delaying action in which the depleted Canadian 2^nd Division suffered another 600 casualties.

When he appreciated that the British and Canadians had crossed above Rouen and that the leading US forces were at Soissons, Generalfeldmarschall Walter Model, the Oberbefehlshaber 'West', decided that his Heeresgruppe 'B' must yield the lower reaches of the Seine river and withdraw to the 'Dieppe-Linie' with General Gustav-Adolf von Zangen’s 15^th Army holding the area from Dieppe to Neufchâtel and the 7^th Army (now under Eberbach’s command once more) from there to the Oise river. The rest of the front would be held by the 5^th Panzerarmee and General Kurt von der Chevallerie’s 1^st Army. These positions were to be occupied on 31 August, but by this time Model’s thinking had been overtaken by events, and during the morning of that day Adolf Hitler was compelled to agree to Model’s suggestion for a withdrawal behind the line of the Somme river.

On 29 August, therefore, the last German resistance in the area to the west of the Seine river ended, although heavy rain and the proximity of Allied troops prevented air attacks on the Germans' final evacuation. On 30 August the Canadians entered the nearly deserted city of Rouen, while the rest of the Canadian II Corps began to cross the Seine river in strength and the I Corps on its left hurried to get over the river farther downstream by any means it could.