Just months before, in early December 1917, General Haig had adopted the German doctrine of defence in depth, which dictated three zones of defence: the forward zone, the battle zone and the rear zone. However, in many cases the British officers in charge of various parts of the line did not understand how to implement this defensive strategy. This failing helped lead to the near-total collapse of the British lines in late March 1918.

The main principle of the defensive doctrine was the establishment of a thinly manned front line that was dependent on mutual fire support to check any enemy advance in the forward zone. The troops there were expected to fight to the last man if necessary, launching localised counterattacks to reclaim lost positions. They were expected to hold out against everything except a major attack; if this occurred, the main battle would be fought in the battle zone, 3 or 5 kilometres to the rear. It was here that the bulk of infantry, trenches, wire, machine guns and field artillery would be located, and it was here that any breakthrough by the enemy would be halted. It was sufficiently distant from the enemy’s front line to impede the use of its artillery, leaving the enemy vulnerable to counterattacks. The fortified rear zone, behind the battle zone, would be used to coordinate and generate any counter-attack required to repel the enemy’s advance.1

All good on paper, but for those on the ground it was far from reality, as recorded by an unnamed officer of the British 36th Infantry Division: a ‘spirit of unjustified optimism prevailed amongst the Higher Commanders. They were hypnotised by the Red in defences of the Battle Zone on their maps. Those showed elaborate trench systems protected by strong barbed-wire entanglements. To these were added arcs of fire of machine guns and artillery barrages that not only did not exist, but in all probability, and as it turned out, would never exist. In trench warfare, these Commanders and their staff had so little to do that they indulged in a form of map warfare from which they were unable to divorce themselves when operations away from a set piece occurred.’2

Some commanders continued with the old doctrine of heavily manning the forward zone, to stop the enemy there. Those either side of them might do the same, or decide to hold their troops back in the battle zone. The officer from the 36th Infantry Division wrote a week before the German offensive that after touring the lines he realised that while his corps was going to hold the line in depth, the next corps to his right was holding the forward zone in strength. When this was made known to the staff of the Fifth Army, the reply was merely that the two corps were to settle the matter between them! This was a recipe for disaster, as each could readily be flanked by any successful German penetration.3

It was not only the German tactics and massive reinforcements that broke through the British lines on 21 March, but also the inability of the British forces on the ground to understand the doctrine of defence in depth: ‘It was due to a defensive system that was not understood, did not work and did not properly exist.’4 The British had always considered themselves an attacking force, and used trench systems to launch attacks from; this was at the heart of the confusion. The concept of strategic defence was anathema to them. They and other Allied troops believed they had to attack and push the Germans out of France and Belgium to win the war – anything less was defeat.5

Another important factor contributing to the German breakthrough was that German doctrine was based on initiative and flexibility. The British retained very much a hierarchical structure, and often troops (and senior officers) waited for orders rather than using their initiative and taking command of a situation as it unfolded. They would all too often either be overtaken by events (and German stormtroopers) or be forced to fall back, looking for a command structure or reserves that no longer existed. The situation continued to snowball out of control.6 Even when a consolidated force was available for counterattack, it was often fragmented and dispersed. A staff member of the British 20th Infantry Division (Fifth Army), which was released on 21 March, was clearly frustrated by the piecemeal attempt to hold back the German advance: ‘What was the result? Was the 20th Division used for the counter attack? Not a bit of it. One brigade was put in to help the 36th Div. & the other two were strung out all along the rear zone to act as a net on to which, and through which, the Corps was to retire. The 20th Division as an offensive unit ceased to exist . . . In my view this was the turning point between the active offensive-defensive visualised in the Corps scheme and the passive defence which so quickly deteriorated into a disorganised retirement.’7

There was a real danger that a wedge would be driven between the British and French armies, as neither the French nor the British had any strong reserve force available to plug the line. Haig’s and Pétain’s pledges of mutual support came to nothing: the French were initially reluctant to aid their hard-pressed ally and were worried about defending Paris, while by 24 March a rather distraught Haig was arguing for the need to break contact with the French in order to maintain his fighting force, and in the process abandon the British Fifth Army. Haig expressed so to General Byng, commanding the British Third Army, stating that the ‘BEF [British Expeditionary Force] had now to safeguard itself and that no help could be expected from the south. [Haig] made it quite clear that any further withdrawals must be in a North West direction and the Third Army must safeguard the right flank of the BEF by swinging its own right back [away from the French]. Sir Douglas also took it for granted that no help was to be expected from the remains of the Fifth Army.’8

Even though the French were concerned about Paris, they soon realised they had to support the British southern flank in order to ensure their own survival. Within 24 hours of the German offensive, they committed two infantry divisions and one cavalry division to support the Fifth Army, and by 26 March had committed nine infantry divisions, with 15 more on the way north to help buttress the British lines. Still the German offensive advanced, trying to drive the French and British armies apart.9

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Meanwhile, every available Allied aircraft was flying behind the German front dropping bombs and strafing the congested roads with machine-gun fire. The roads were crucial in supplying the German advancing troops with stores, food, materials, ammunition and artillery, and were attacked around the clock. The two Australian scout squadrons, No. 2 and No. 4, were heavily involved in these operations, flying in relays. Each had recently been outfitted with the best aircraft then available: No. 2 Squadron with the superb SE5a – probably the best fighter of the whole war – and No. 4 with the legendary Sopwith Camel.10 Fighter squadrons were now tasked with attacking ground targets, with No. 4 Squadron alone dropping over 3 tonnes of bombs and firing over 67,500 rounds of machine-gun bullets. While No. 2 Squadron for a time was used to conduct high-altitude patrols, it too was soon involved in extensive ground-attacking operations.11

Lieutenant Arthur Cobby, a 24-year-old bank clerk from Glenhuntly, Victoria, and a former soldier with the 47th Battalion, was now an airman with the No. 4 Squadron, and recalled flying one such mission: ‘[It was] almost impossible [to miss] . . . one only had to fly straight over a road for a few seconds. And let the bombs go one after another as quickly as possible, and they fell amongst masses of marching troops.’12 With the ongoing heavy demand to continue the air campaign around the clock, Cobby said that ‘it was not long before we were all starting to show signs of strain . . . my principal trouble was that I could not eat, but champagne and brandy, with an odd biscuit, seemed good enough’.13

These attacks did much to disrupt the German advance and caused confusion. The crowded road networks became obvious targets, with bombs and machine guns inflicting serious destruction. They ‘wrought hideous damage in the German columns; they blocked main roads for hours when time was the essence of full victory for the Germans; they saved the broken armies on the ground from ruin’.14 However, the airmen paid a price. Ground fire, dogfights and, perhaps more crucially, the exhausted state of the flyers meant that casualties accumulated fast. Lieutenant Henry Forrest, a 21-year-old clerk from Melbourne with No. 2 Squadron, recalled the death on 28 March by anti-aircraft fire of his mate Lieutenant Thomas Hosking, a 25-year-old engineer from St Kilda, Victoria, who had fought at Gallipoli with the 8th Battalion: ‘We were diving on the enemy . . . from about 1000 feet and Hosking was a couple of hundred yards from me when I suddenly saw his right top wing and his tail break off, apparently a direct hit from a shell. He crashed in a hopeless mess just behind the German front line. I circled around his machine for a few minutes but there was no movement near it.’15

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With the Fifth Army in retreat, it was not long before the Germans succeeded in isolating elements of the Third Army – the next in line. The beginning of the rolling-up of the British southern flank had apparently begun. The Third Army held the southern flank of the huge Flesquières salient bulging into the German lines, which the British had captured in 1917 – the Germans planned to isolate the British divisions using pincer movements north and south. While Haig had been aware of the danger of this salient, he had earlier decided not to give up hard-won ground. With the Fifth Army in retreat, the southern flank of the Third Army was now hanging in the air and the British troops in the salient were in danger of being cut off and surrounded. For two days General Byng’s Third Army stubbornly held its position, frustrating the German plans, but the inevitable happened and the British were forced to withdraw, broadening the gap in the line. The Germans now advanced across the old Somme battlefields of 1916.16

Meanwhile, Haig placed those portions of the Fifth Army that were north of the Somme river under the command of Byng. This included the British 9th (Scottish) Infantry Division, which had performed magnificently in helping to stem the northern advance of the Germans. Every Allied soldier who could be found was thrown into the battle, including the men of the 1st South African Infantry Brigade, then assigned to the 9th Division and who, on 24 March, had momentarily checked the German onslaught around Péronne. The British infantry and artillery had withdrawn, exposing the flanks of the South Africans, which were covered by only a few tanks. The Germans set fire to the tall dry grass and outflanked the South Africans in the smoke; the South Africans stubbornly fought on regardless, but were soon surrounded and virtually wiped out. Among those few who managed to escape was Captain Geoffrey Lawrence, who recalled passing enormous shell craters. In one of these they came across some of their wounded, and he distinctly remembered one, who was almost a boy, pleading not to be left behind. Lawrence could only tell him that he was certain the Germans would look after them: ‘It was terrible having to leave them to their fate! He kept pleading, “Don’t leave us, sir.” That rang in my ears for a long time.’17 Around 300 South Africans, who had been separated from their brigade before this action, would continue the fight. They quickly formed a composite South African battalion, which was attached to the British 26th Brigade.18

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For days Haig had been trying to get Pétain to maintain contact with the southern flank of the British line. French help was provided, but the French divisions were thrown into battle piecemeal, often without artillery support, and this resulted in terrible casualties with nothing to show for the sacrifice. While Pétain was still concerned that the main German attacks might yet fall against his front, he was just as concerned as Haig to keep the two armies unified. Haig wrote in his diary on 24 March, regarding the first of two meetings that day with Pétain: ‘General Pétain arrived at 4 p.m. He has arranged to put 2 Armies under General Fayolle on my right, to operate in Somme Valley and keep our two Armies in touch with one another. Pétain is most anxious to do all he can to support me. The basic principle of cooperation is to keep the two Armies in touch. If this is lost and the Enemy comes in between us, then probably the British will be rounded up and driven into the sea!’19

Haig claimed that Pétain in the second meeting of 24 March, held at around 11 p.m., decided to abandon the British flank and withdrew south-west to protect Paris. However, subsequent scholarly research into this much-talked-about meeting indicates that it was likely Pétain who emphasised to Haig that the French and British above all else needed to stay together, and Pétain who was concerned that the British might abandon their current line and withdraw towards the Channel Ports.20 Pétain stated to Haig that if the British ‘retreated north-west to the Channel Ports, then, if necessary, the [French] Montdidier divisions would fall back south-westwards towards Beauvais, to cover Paris’.21

Haig was allegedly shocked, believing that Pétain was going to break contact to protect Paris. The only way to avoid losing the war was to ensure that the British and French forces remained united. To do otherwise would result in each being defeated in detail – the British, followed by the French. Later stating that he believed Pétain had lost his nerve, Haig said he telephoned CIGS Henry Wilson in London at around 8 p.m., asking that he come over. However, this telephone conversation occurred three hours before Haig and Pétain had their second meeting on 24 March. Haig’s diary entry makes it clear that it was in this second meeting that Pétain said he was going to retire towards Paris.22 CIGS Wilson was requested to come out by a distraught Haig before this second meeting with Pétain. Haig considered withdrawing towards the British Channel, abandoning the Fifth Army – he had made a statement to that effect to General Byng just days earlier. To him it was crucial that the British Third Army remain in contact with Haig’s right flank, as opposed to maintaining ‘contact’ with the now-retreating dispersed elements of the Fifth Army south of it.23

On arriving in France, Wilson recorded in his diary that Haig seemed cowed and said ‘it would be better to make peace on any terms we could’.24 This might explain Haig’s later misunderstanding, or perhaps misrepresentation, of Pétain’s statement regarding the need to ‘cover Paris’ if the British fell back towards the Channel Ports. Indeed, when first agreeing that a supreme Allied commander should be appointed, Wilson asked Haig who should it be, and Haig without hesitation nominated Pétain. It is hardly likely that he would have put forward Pétain for the lofty position if he had such deep concerns about Pétain’s plans to break contact with the British and retreat towards Paris.25

On 26 March, a crucial meeting was held at Doullens in France, not far from the advancing Germans. A decision had to be made. Present were the British prime minister, the French president, generals Haig, Pétain and Foch, and a number of other senior Allied representatives. At the historic meeting Foch was nominated the supreme Allied commander. In his later published diary Haig took full credit for Foch’s appointment: ‘It was proposed that Foch should be appointed to co-ordinate the operations at Amiens. I at once recommended that he should co-ordinate the action of all the Allied Armies on the Western Front. Both Governments agreed to this.’26 At the time Foch was not overly happy about the outcome, stating that he was being given the task of winning a battle that had already been lost. Even so, with his appointment the critical decision had been made, and with it a new spirit of optimism and confidence occurred in Haig and his staff.

Following the conference a communiqué was quickly issued to all troops stating that there must be ‘NO withdrawal’ except locally, and then only due westward, so as ‘NOT’ to separate one army from the other.27 That said, it was estimated that between 21 and 26 March the British had lost nearly 75,000 men – almost 10 per cent of their total strength along the Western Front.28