In 2001, Caddick-Adams also wrote of the chronic lack of battlefield communication within and between the British and French divisions, which was caused by a shortage of radios and led to elementary and costly tactical errors.

The possibility of an encirclement of the Allied armies' northern group is beginning to take shape.At 8:30 a.m., RAF Air Component Hawker Hurricane pilots reported a German column at Marquion on the Canal du Nord and others further south.

Saar Force was composed of the 51st (Highland) Infantry Division (Major-General Victor Fortune) and attached mechanised cavalry regiment, machine-gun battalions, artillery, French troops and a composite RAF squadron of fighters and army co-operation aircraft.

More attacks followed on the Franco-British positions and on 15 May, the division was ordered back to the ligne de reçeuil, before being relieved by the night of 22/23 May to concentrate at Étain, 25 mi (40 km) west of Metz.

The area south of the lower Somme was the Northern District of the BEF supply system (Acting Brigadier Archibald Beauman) with sub-areas at Dieppe and Rouen.

Early that day, part of the 1st Armoured Division advanced to the Bresle on a line from Aumale to Blangy, as reports were received that the German forces on the southern flank were on the defensive, only reconnoitring south of the river as they attacked St Omer and Arras in the north.

[10] On the night of 22/23 May, Allied forces north of the Somme were cut off by the German advance to St Omer and Boulogne, which isolated the BEF from its supply entrepôts in Brittany, at Cherbourg in Normandy and at Nantes.

[12] Vicforce (Colonel C. E. Vickary) took over five provisional battalions, created from reinforcement troops in BEF infantry and general base depots, which held plenty of men but few arms and little equipment.

When German troops captured Amiens on 20 May and then began patrolling south of the river, their appearance caused panic and alarmist reports, in the absence of reliable information.

[12] On 21 May, Panzergruppe von Kleist prepared the Somme bridges for demolition and outposts were pushed as far south as Moyenneville, Huppy, Caumont and Bailleul, where anti-tank guns had been dug in and camouflaged among the woods.

The groups at Ailly and Picquigny could not reach the river due to the strength of the German forces holding the bridgeheads, the Borders suffering many casualties and the Bays several tanks.

Evans thought that the British division, arriving piecemeal, with the support group and an armoured regiment diverted to Calais, with no artillery and with the French Seventh Army unprepared, could not achieve such an ambitious objective but he had to try.

[17] Georges passed orders to the Swayne Mission, the British liaison organisation at GQG, that the 1st Armoured Division was to mop up the Germans south of Abbeville, while the Seventh Army crossed the Somme.

[20] On 26 May, orders for the attack were issued, the 2nd Armoured Brigade came under the 2e Division Légère de Cavalerie (2e DLC, Colonel Berniquet) to take high ground from Bray to Les Planches, which overlooks the Somme south-east of Abbeville, with support from French artillery and infantry.

The 3rd Armoured Brigade was subordinated to the Division Légère de Cavalerie (5e DLC) for an attack on high ground from Rouvroy to St Valery-sur-Somme, also with French artillery and infantry in support.

[25][c] The 4e DCr arrived, which although improvised, incomplete and having suffered many losses earlier in counter-attacks at the Battle of Montcornet (17 May), was much more powerful than the French cavalry divisions used hitherto and could field 137 tanks, 14 armoured cars (32 Char B1s, 65 Renault R35s, 20 SOMUA S35s, 20 Hotchkiss H35 modèle 39s and 14 Panhard 178s).

The German front line was held by two battalions of Infanterie Regiment 217 reinforced by two companies of the Motorisierte Panzerabwehrabteilung 157 with an establishment of forty-eight 37 mm Pak 36.

The tanks had great difficulty overcoming French barricades at Bellevue and were harassed by accurate German 105 mm howitzer fire, which could crack the deck armour with direct hits.

The German III Battalion on the eastern flank had been routed, spreading panic in the Caubert area with tales of French Ungeheuer (monsters) and Stahlfestungen (steel fortresses).

It was estimated that only about 75 men still had sufficient morale to defend themselves and the bridgehead collapsed, as the western flank had to be withdrawn to avoid it being encircled, reducing the area held by the Germans to about a sixth of its original extent.

He ordered the tank units to rest and regroup during the night, ready to renew the advance at first light (4:00 a.m.) The respite allowed German command to recover and organise a new defensive perimeter.

An important part of the German defence was Flak-Abteilung 64 which fielded about sixteen 88 mm guns, the armour-piercing ammunition of which could easily penetrate the Char B1 frontal armour.

[34] In the early morning, the Char B1s cleared the lower western and southern slopes of Mont de Caubert, against little resistance from the German infantry and destroyed a 105 mm howitzer position for the loss of one tank.

German counter-attacks around Cambron became so threatening, despite the deployment of a battalion of the 51st (Highland) Infantry Division, that French cavalry tanks were moved from the east to the west side of the bridgehead to repulse them; a lull fell in the evening.

[40] The failure of the French, completely to reduce the bridgehead, was caused by the German defenders, fatigue of the troops, tank losses and a false impression given in the order by De Gaulle, that the battle had already been won.

[44] From 1 to 3 June, the 51st (Highland) Infantry Division (still over-strength because of the attachments for Saarforce), the Composite Regiment and the remaining elements of the 1st Support Group, relieved the two French divisions opposite the Abbeville–St Valery bridgehead, with the 153rd Infantry Brigade in reserve on the Bresle from Blangy to Senarpont; 9 mi (14 km) of the river on the right were held by a small force, with the Composite Regiment further back between Aumale and Forges; downstream, a pioneer battalion held a 16 mi (26 km) stretch.

Several tanks triggered mines, blew up or caught fire and more were knocked out by the German guns but the rest reached the foot of Mont Caubert and Mesnil Trois Foetus.

The 4th Seaforth were due to follow up supported by light tanks and when three arrived, they advanced on the south-east side of the woods near Villers, where they were received by massed machine-gun fire from Mont de Caubert and repulsed.

The German bridgeheads has not been destroyed and a British and two French armoured divisions had been depleted by the loss of 200 tanks and 2,000 infantry, in which state they were incapable of forming a mobile reserve to defend the Weygand Line.

[53] On 5 June, Fall Rot (Case Red), a German offensive to complete the defeat of France began and Army Group A (Colonel General Gerd von Rundstedt) attacked either side of Paris towards the Seine.