The 'Battle of Boulogne' was the Allied defence of the English Channel port of Boulogne against German attack (20/25 May 1940).

The battle was fought at the same time as the 'Siege of Calais', just before the 'Dynamo' evacuation of the British Expeditionary Force and other Allied troops from Dunkirk. After the Franco-British counterattack at the 'Battle of Arras' on 21 May, German formations and units were held ready to resist a resumption of the attack on 22 May. General Heinz Guderian, commander of the XIX Corps (mot.) of three Panzer divisions, protested that he wished to drive quickly to the north up the English Channel coast to capture Boulogne, Calais and Dunkirk. An attack by part of the XIX Corps (mot.) was not ordered until 12.40 on 22 May, by which time the Allied troops at Boulogne had been reinforced from England by most of Brigadier W. A. F. L. Fox-Pitt’s 20^th Guards Brigade.

The brigade had time to dig in around the port before Generalleutnant Rudolf Veiel’s 2^nd Panzerdivision, which had been delayed by French troops at Samer, attacked the perimeter held by the 2/Irish Guards at around 17.00 and were driven off after an hour of fighting. The 2/Welsh Guards' front came under attack at 20.00 and again at dusk, cutting off a party of the Irish at 22.00. At dawn on 23 May, the German attacks resumed, eventually pushing the defenders back into the town. About 80 light bombers of the Royal Air Force flew sorties in support of the port’s defenders.

Royal Navy warships shot their way into and out of the harbour: French and British destroyers bombarded German positions as wounded and non-combatants were embarked and a naval demolition party was landed. During a lull in the afternoon of 23 May, the Luftwaffe bombed the harbour, despite being intercepted by RAF fighters. At 18.30 the 20^th Guards Brigade was ordered to re-embark, and British destroyers ran the gauntlet of German tanks and artillery to dock. The French defenders above the lower town could not be contacted and only in the morning of 24 May did Général de Brigade Pierre Louis Félix Lanquetot, the commander of Boulogne defence forces, realise that the British had departed.

The French and the remaining British troops held out until 25 May and then surrendered. Guderian wrote that the halt order and the retention of considerable forces to guard against Allied counterattacks lost the Germans an opportunity quickly to capture the English Channel ports off the march and to destroy the Allied forces in northern France and Belgium. An advance on Dunkirk began on 23 May but was halted on the following day until 27 May. Dunkirk was not captured until 4 June, by which date most of the British Expeditionary Force and many French and Belgian troops had escaped.

Boulogne, Calais, Dunkirk and Dieppe are English Channel ports on the French side at the narrowest part of the English Channel. Boulogne lies at the mouth of the fast-flowing Liane river, which winds through a valley. The harbour is on an area of level ground on each side of the river, well built-up and with steep roads up to the old town. The rolling hills, and in particular the Mont St Lambert ridge, provide hidden approaches to the port and offer commanding high ground to an attacker. During the 'Phoney War' from 3 September 1939 to 10 May 1940, the steadily growing British Expeditionary Force had been supplied through ports farther to the west, such as Le Havre and Cherbourg, but the English Channel ports came into increasing use once mine barrages had been laid in the English Channel late in 1939, and this served to effect a useful reduction in the demand for ships and escorts. When leave for men of the British Expeditionary Force began in December, Boulogne came into use for communication purposes and troop movements.

On 10 May 1940, the Germans began their 'Gelb' invasion of the Netherlands, Belgium, Luxembourg and France, and within a few days the Germans had achieved their 'Sichelschnitt' breakthrough against the centre of the French front near Sedan and drove to the west down the valley of the Somme river. As the British Expeditionary Force withdrew through Belgium into north-eastern France, fewer supply troops were needed as the lines of communication shortened, and the British therefore began to withdraw surplus manpower through Boulogne and Calais, and on 17 May Lieutenant General Sir Douglas Brownrigg, the British Expeditionary Forces' adjutant-general, shifted the force’s general headquarters from Arras to Boulogne without informing his French liaison officers. The Germans captured Abbeville at the mouth of the Somme river on 21 May, cutting off the Allied troops in north-eastern France and Belgium from their bases farther to the south.

The defence of Boulogne was the responsibility of the French navy, which had a garrison of 1,100 men in the port’s 19^th-century forts under the command of Capitaine de Vaisseau Dutfoy de Mont de Benque. Eight British 3.7-in (94-mm) anti-aircraft guns of the 2^nd Heavy Anti-Aircraft Regiment, eight machine guns of the 58^th Light Anti-Aircraft Regiment and a battery of the 2^nd Searchlight Regiment had arrived from England on 20 May; the French had two 75-mm (2.95-in) field guns, two 25-mm anti-tank guns and two tanks, one of which was unserviceable. On 20 May, the foremost elements of the XIX Corps (mot.) reached Abbeville, and the northern English Channel ports became the only means of supply and, if necessary, evacuation for the Allies. In the early hours of 21 May, Dutfoy ordered the naval garrison to retire behind the thick mediaeval walls of the Haute Ville, to the east of the Liane river.

Dutfoy heard alarmist reports of the approach of a large German force, apparently from Colonel Jean Pelissier de Féligonde, commander of the 137ème Régiment d’Infanterie, which had been attacked by German tanks at Hesdin, 30 miles (48 km) to the south-east of the port. Dutfoy ordered his men to disable the coastal artillery in the forts and to head for the harbour for evacuation, and these orders were amplified by other officers. Dutfoy left for Dunkirk in the early hours and French discipline disappeared: looters broke into a naval store and drank the alcoholic contents. Civilians still waiting for places on evacuation ships began to panic, until Capitaine de Frégatte Poher, in charge of the sea front, threatened the crowd with a gun, but Poher decamped at 10.00 and the spiking of the naval guns continued. Some of Dutfoy’s men contacted Vice-Amiral Marcel Leclerc, the deputy commander of Dunkirk, who ordered the remaining guns to be preserved for the defence of the town. On a visit to Boulogne early on 22 May, Leclerc ordered the sailors to fight it out and wait for relief by the French and British armies, and Amiral Jean Abrial, the French commander at Dunkirk, ordered that 'You are to die at your posts one by one rather than give in…'

A detachment of Royal Marines reached Boulogne in the early morning of 21 May. The 20^th Guards Brigade, comprising the 2/Welsh Guards and 2/Irish Guards, was training at Camberley on 21 May, when it was ordered to embark for France. With the brigade anti-tank company and a battery of the 69^th Anti-Tank Regiment, Royal Artillery, the Guards brigade arrived in Boulogne in three merchant ships and the destroyer Vimy, escorted by the destroyers Whitshed and Vimiera. Lanquetot’s French 21ère Division d’Infanterie was to hold a line between Samer and Desvres, about 10 miles (16 km) to the south of the town, where three battalions had already arrived. Further British reinforcements, including a regiment of cruiser tanks, were expected from Calais on the following day.

Fox-Pitt deployed his men on the high ground outside the town, liaising with Lanquetot, who organised the French troops in the town. The 2/Irish Guards held the right flank to the south-west from the river at St Léonard to the sea at Le Portel, and the 2/Welsh Guards the left flank to the north-east of the river on the western slopes of Mt Lambert ridge and high ground through St Martin Boulogne, which made a defensive perimeter of 6 miles (9.7 km). Road blocks had been established by a party of about 50 men of the 7/Royal West Kents from Albert, about 100 men of the 262^nd Field Company, Royal Engineers, and anti-aircraft crew held the right flank of the 2/Welsh Guards along the roads approaching from the south. Fox-Pitt had left a gap in the perimeter between the Welsh left flank and the coast to allow for the arrival of the reinforcements expected from Calais. In the town awaiting evacuation were 1,500 men of Lieutenant Colonel D. Dean’s No. 5 Group Auxiliary Military Pioneer Corps, a mix of recalled reservists and part-trained troops working as labourers. Under French command were the fort garrisons and some French and Belgian training units of limited military value. Lanquetot had told Fox-Pitt that the French forces in Boulogne were 'folded up', which Fox-Pitt inferred meant that they were ready to give up.

The Franco-British counterattack at Arras led the Germans to continue to attack to the north toward the English Channel ports rather than south across the Somme river, and late on 21 May, the Oberkommando des Heeres ordered General Ewald von Kleist’s Panzergruppe 'von Kleist' to advance about 50 miles (80 km) to the north in order to capture Boulogne and Calais. Apprehension about another counterattack led von Kleist to hold back General Hermann Hoth’s XV Corps (mot.), shift one division of General Georg-Hans Reinhardt’s XLI Corps (mot.) to the east, and the detachment of Generalleutnant Ferdinand Schaal’s 10^th Panzerdivision of Guderian’s XIX Corps (mot.) to guard against a counterattack from the south. Parts of Kirchner’s 1^st Panzerdivision and Veiel’s 2^nd Panzerdivision, both formations of the XIX Corps (mot.), were also held back to defend bridgeheads over the Somme river.] The 2^nd Panzerdivision was ordered to advance to Boulogne on a line from Baincthun to Samer, with the 1^st Panzerdivision as a flank guard on the right, advancing to Desvres and Marquise in case of a counterattack from Calais.

The 2^nd Panzerdivision formed two columns, one of them to circle round the town and attack from the north. The southern column made contact first in the early afternoon of 22 May against the headquarters company of the 48ème Régiment d’Infanterie, the only troops of the 21ère Division d’Infanterie between the Germans and Boulogne. The French clerks, drivers and signallers sited two 75-mm (2.95-in) field guns and two 25-mm anti-tank guns to cover the crossroads at Nesles, where they delayed the Germans for almost two hours until they were outflanked. The German column reached at the outskirts of Boulogne in the evening and began shelling and probing the 2/Irish Guards' positions to the south of the town. The Irish knocked out the leading German tank and repulsed later attacks despite the fact that the Germans had overrun one of their forward platoons. In the early hours, the Germans attacked the 2/Welsh Guards' positions along the coast from the north-east as they began to envelop the town, but were forced back each time. Together with Fox-Pitt’s only communication link with England, Brownrigg departed with his staff at 03.00 on the destroyer Verity, without informing the Guards brigade. Only a few troops of the 21ère Division d’Infanterie were able take up its blocking positions near Desvres before the German advance reached them. The French managed to delay the 1^st Panzerdivision here for much of 22 May before Fox-Pitt was informed at 04.00 that the French had been forced back to Boulogne by German tanks. Most of the 21ère Division d’Infanterie, en route to Boulogne by train, was ambushed by German tanks and dispersed.

One hour after dawn on 23 May, Fort de la Crèche near Wimereux, to the north of Boulogne, was captured by the Germans. The possibility of reinforcement from Calais was thwarted by the appearance of German armour at the northern perimeter. Fox-Pitt realised that he would have to defend the port with only his two Guards battalions and the miscellany of French and British troops already there. The AMPC was hastily combed for men with military experience and armed with rifles taken from the others, and these 800 men were rushed into the gap between the two Guards battalions and another 150 were sent to reinforce the 2/Welsh Guards. The anti-aircraft gunners guarding the southern roads destroyed two German tanks with their 3.7-in (94-mm) anti-aircraft guns and then retired.

The Germans started a pincer attack on the positions of the Welsh and Irish Guards, and by 10.00 the southern pincer, backed by artillery and aircraft, had made the open slopes around the town untenable. The Guards were thereby forced back into the town. Generalleutnant Wolfram Freiherr von Richthofen’s VIII Fliegerkorps sent Junkers Ju 87 single-engined dive-bombers to destroy the fortifications at Boulogne, and this greatly aided the attacking forces. Vimy arrived at 12.00 with a naval demolition party and Force 'Buttercup', a Royal Marine shore party, beginning the embarkation of casualties and the AMPC. Fox-Pitt received orders via Vimy to hold Boulogne at all costs. The Royal Navy and a flotilla of French destroyers led by Capitaine Yves Urvoy de Portzamparc, comprising the large destroyers Chacal and Jaguar with the smaller destroyers Fougueux, Frondeur, Bourrasque, Orage, Foudroyant, Cyclone, Siroco and Mistral, provided fire support to the troops on the outskirts of the town.

Veiel found that the British and French in Boulogne were 'fighting tenaciously for every inch of ground' and could not tell if the British were evacuating or reinforcing the port. During a lull in that afternoon, the British destroyer Keith arrived and began embarking AMPC troops. A Luftwaffe raid was intercepted by Supermarine Spitfire single-engined fighters of the RAF’s No. 92 Squadron, but the commanders of both British destroyers were killed by bomb splinters. Frondeur was hit and disabled by Ju 87 dive bombers of the I/Sturzkampfgeschwader 77, Orage was scuttled, and the British destroyer Whitshed was damaged by a near-miss. No. 92 Squadron lost five pilots: two were killed, one wounded and two taken prisoner as one aeroplane was shot down by Messerschmitt Bf 109 single-engined fighters and the other four by Messerschmitt Bf 110 twin-engined heavy fighters. By 15.00, Fox-Pitt had withdrawn his brigade to positions in the town and moved his headquarters nearer to the quay, the better to contact the destroyers, his only link with London. With German artillery having the advantage of observed fire to sweep the docks, he sent a message to London saying 'situation grave'. Shortly before 18.00, Keith received orders for an immediate evacuation of the British and notification that five destroyers were either standing off Boulogne giving fire support or were en route to the port. Fox-Pitt decided to continue with the AMPC evacuation while the Guards conducted a fighting withdrawal to the harbour but communication with the British troops on the perimeter was only possible by despatch rider. The bridges held by the Guards were demolished by the Royal Engineers before the Irish Guards barricaded the streets with vehicles and withdrew to the harbour. The 800 pioneers commanded by Dean were the last to fall back from the perimeter as Dean had been away from his headquarters when the withdrawal order arrived. Armed only with rifles, the pioneers had hoped to obstruct the Germans with makeshift roadblock barricades and claimed to have destroyed one tank by igniting petrol under it. Dean used his reserves to relieve two forward posts which had become isolated, resulting in fierce hand-to-hand fighting.

Vimiera and Whitshed replaced Vimy and Keith, embarking many of the Marines and guardsmen. The harbour was full of ships, and although two Gruppen of Ju 87 dive-bombers failed to hit the ships, their bombs hit the quayside near Vimy and Keith causing some casualties. The destroyers Venomous and Wild Swan arrived and began embarking Force 'Buttercup' and the remainder of the Irish Guards. With Germans in positions overlooking the harbour the Guards and the ships engaged in a duel with the German artillery. German tanks advancing towards the quayside were knocked out by the 4.7-in (119.4-mm) guns of Venomous, one tank turning 'over and over, like a child doing a cartwheel'. German field guns bombarded the harbour as the destroyer Venetia steamed through the narrow entrance channel, and hit the destroyer several times. Fires broke out on the ship, but she was reversed out and made way for Venomous and Wild Swan, which also departed in reverse, Venomous steering with her engines as the rudder had jammed.

On 24/25 May, the destroyer Windsor arrived after dark and was able to continue the embarkation. On clearing the harbour, her captain signalled that there were still British troops requiring evacuation and Vimiera was sent back, arriving in Boulogne at 01.30. The quayside was deserted, but when the captain called out by loud hailer many men appeared from hiding and the destroyer’s crew managed to squeeze them aboard. When Vimiera reached Dover at 04.00, 1,400 men disembarked. Most of the British troops had now left Boulogne, but about 300 Welsh Guards remained. Lack of wireless sets left three of the Welsh Guards forward companies out of touch and by the time they had found out about the evacuation, two companies had been cut off from the docks. The companies split into smaller groups and tried a break-out to the north-east. Lanquetot was based in the Haute Ville, awaiting the arrival of elements of the 21ère Division d’Infanterie, and when he discovered the disaster that had befallen his division, he organised the defence of the town as best he could.

German attacks on the town at 06.00 and 08.00 were repulsed and some German tanks were reported to have been destroyed. The French navy continued its fire support but Fougueux and Chacal were damaged by Luftwaffe attack: Chacal was sunk on the following day by German artillery. During the night, about 100 French soldiers tried to break out toward Dunkirk but failed. At dawn on 25 May, the Germans attempted an escalade using grenades and flamethrowers, supported by 88-mm (3.465-in) guns, and at 08.30 Lanquetot surrendered. The German troops were supported by attacks from the dive-bombers of StG 2. The Stukas demolished the town and had their first encounter with RAF Fighter Command and lost four aircraft over Boulogne and Calais.

The last British unit in Boulogne was No. 3 Company, 2/Welsh Guards, which did not reach the docks until daybreak only to find that Vimiera had departed. Major Windsor Lewis took over a large party of stragglers in the sheds at the quayside comprising guardsmen, 120 French infantry, 200 AMPC, 120 Royal Engineers and 150 civilian refugees; most of the pioneers were unarmed. When the sheds came under German fire, Lewis moved the group into the Gare Maritime harbour railway station and had sandbag barricades built. On the evening of 24 May, under fire from tanks and machine guns, this extemporised force repulsed a German party which approached the quay in a boat. Without food, short of ammunition and with no hope of evacuation, the force surrendered at 13.00 on 25 May. In all, the Germans captured some 5,000 Allied troops in Boulogne, the majority of whom were French. Many of the prisoners were put to work repairing the harbour fortifications to resist a possible British amphibious assault.

In the British official history it is written that the battle showed 'how easily misunderstandings may arise between allies in such a confused situation'. The 20^th Guards Brigade had retired toward the outskirts of Boulogne on the morning of 23 May, after resisting attacks from all sides from 07.30. Lanquetot signalled that the British were withdrawing precipitately, perhaps unaware of how fiercely the withdrawal was being contested. Communication between Fox-Pitt and the French headquarters at the Citadel was cut by the German advance between the Citadel and the Guards positions in the lower town. Fox-Pitt received orders to evacuate British troops but not the French. On the morning of 24 May, when Lanquetot discovered that the British had gone there were French complaints about British 'desertion'. To the British, the 20^th Guards Brigade had been sent to Boulogne at short notice to hold a British Expeditionary Force trans-shipment port, and when it became redundant the two battalions, insufficient to hold the town, were withdrawn.

Allegations that the British had deserted the French may have influenced Prime Minister Winston Churchill to order the garrison at Calais to fight to the finish during the siege. The decision was controversial as the British at Calais could have been evacuated after they had slowed the German advance toward Dunkirk. The official historian wrote that the five-hour delay of the XIX Corps (mot.)'s attack on Boulogne on 22 May, ordered by von Kleist, had been criticised in the corps' war diary. Keeping the 10^th Panzerdivision in reserve during the attacks on Boulogne and Calais meant that the Aa Canal line, the western perimeter of the Dunkirk defences, could not be attacked simultaneously. Without the delay, the preparations of the 20^th Guards Brigade in Boulogne might also have been interrupted. The long, exposed flank of Heeresgruppe 'A', the uncertain German hold on Amiens and Abbeville, and the Allied retention of Arras meant that the advantageous situation enjoyed by the Germans on 22 May could have changed to the benefit of the Allies. The German delay was not excessive, since it was not known if the Allied counterattack at Arras was over.