British Prime Minister David Lloyd George first agreed in principle to extend the length of line occupied by the British Army in France at the Anglo-French Boulogne Conference in September 1917. He then asked Commander-in-Chief Sir Douglas Haig to consider this and report. Haig did so on 8th October: he insisted that in view of the now-doubtful power of the French army to resist a German attack that all other British fronts should be placed on the defensive; all remaining force should be concentrated on the Western Front and take an offensive stance; the 62 British Divisions now in France be brought up to full strength, and that the occupied line should not be extended. He was applying the well-known military maxim of concentration of force at the decisive point.
At a meeting of the War Cabinet three days later, Lloyd George sidelined Haig’s report and himself outlined various strategies for the war, with special attention to operations against the Turks. He invited Sir John French [who had been removed from command in 1915 and continued to harbour ill feeling towards Haig and the Chief of the Imperial General Staff, Sir William Robertson] and Sir Henry Wilson [being manoeuvred by Lloyd George to wrest control from them both – see Boulogne conference] to offer their opinions. Both men advised a course of action that would require the establishment of a politico-military Allied body that would advise on these matters.
Wilson met Foch with Lloyd George on 9 October, and he recommended that the British should take over more line. Commander-in-Chief Philippe Petain asked the British to relieve his Sixth Army down as far as Barisis, which meant a front requiring six more Divisions in the front line. Haig said he would do his best, but knew that this move was the end of Allied aspirations for continuation of the offensive. On 3 December 1917, Haig ordered all of his Army Commanders to organise their zones for defensive purposes.
Lloyd George and Wilson had set in train a strategic change that would have dire consequences for the British Army.
The British Army was already carrying the load
Whilst at this time the French Army held more than 350 miles of front compared to the British 100, it was the British front that was the most critical by late 1917. Most of the French line was quiet, with Pétain having placed his army on a passive defensive since the mutinies of April 1917. Actual Allied strength in terms of men was that the French had 972 battalions of infantry, the British 806, yet since mid year it had been the British army that took the fight to the enemy. In consequence the German army had moved nearly half of its total force to face the BEF.
With limited forces, extending the line meant stripping men away from other sectors
Haig’s dilemma was how to find he forces needed to hold the longer line. The space between the front line in Flanders and the all-important Channel ports was very narrow, and it was full of vital lines of communication. Any withdrawal in this area, forced by enemy action, would have dire consequences for the ability of the British – and hence the Allies – to continue to wage war on the Western Front. Haig had little room for manoeuvre in terms of reducing the force in Flanders. To the south where the extension was planned, this was not so. A withdrawal of say 40 miles would not have real strategic consequences. It could be held with relatively fewer men, as long as insurance was there in the form of reserves that could be moved quickly to the area should the Germans attack and break through.
Gough: “…by the end of November we were able to make a good guess that our destination was the French front on the right of Third Army. Up to this date this had been a quiet sector and held by two French Corps only; but though quiet at the moment, it was a considerable addition to the British front – about 28 miles – to which Haig very naturally objected and against which he strongly protested“. “…the enemy [here] was very active in making raids and took a prisoner or two from us regularly…and this was the first sign which came to my notice that our front was likely to be the one selected for attack by the Germans“. By 14 December 1917, Pétain was pressing for the relief of his Sixth Army and a further extension of the British line.
Fifth Army find the line indefensible; set to work to make it so
“The trench system was in a very neglected state. On some parts of the front there was no continuous line, no dugouts or observation posts, and communication trenches were few and provided inadequate cover…it had naturally been organised to receive from and deliver towards Paris. It now had to face towards the British centres of activity…I saw to my surprise parties of French civilians busy filling in trenches and removing wire along a line…east of Villers-Bretonneux. Almost my first act … was to stop all further demolition … and commence its reconstruction”. “Nothing existed in rear beyond a good line of wire”. By 17th December: “Telephone lines on this front had not been buried and it was estimated that it would now require 500 men working continuously, two or three months, to carry out this important work properly“.
French push for British to extend even further
On 15 December 1917, the War Office cabled Haig to say that new French Prime Minister Clemenceau – he took office in November – had threatened to resign if the British did not extend as far as Berry-au-Bac, a further 37 miles of front on from Barisis. Haig reluctantly arranged with Pétain to extend down to a short distance beyond the River Oise. The extension of the line began on 10 January 1918, with Lieutenant-General Sir Hubert Gough’s Fifth Army being given the unenviable task of preparing to be attacked.
Just not enough manpower to do all the work necessary
“Correspondence with GHQ eventually produced an army of labour amounting to 68000 men, but a large proportion of these did not arrive till March and they were not able to do much in the week or two at their disposal before the attack fell on us. The Labour Corps was so organised that every man had a day’s rest once per week and we could count only on 48000 – a little more than 1000 per mile of [Fifth Army] front, after deductions for men sick or on leave. On 9th March, of this 48000 about 7000 were prisoners of war who were not permitted to work in the forward areas, 18000 British from Labour Battalions, 3000 Indians, 4000 Chinese and 7500 Italians. Its work consisted of making railways, roads, bridges, preparing sidings, platforms and dumps of ammunition, huts, aerodromes, etc in addition to the defences. Five days before the battle about 10000 men were employed on roads, 4500 on railways, 7000 on depots, dumps, etc and 3500 on hutments, leaving less than 9000 available for [work on] defences”
The consequences would soon be all too apparent, when the German Army attacked on 21 March 1918 and over the next few days all but destroyed Gough’s Army.