David Lloyd George, Britain’s then future prime minister, despaired within months of the outbreak of the first world war that the conflict risked continuing indefinitely as war ministers searched in vain for a “blow that would end the war once and for all”.

Cabinet papers show how Lloyd George, below, presciently warned his war cabinet colleagues in early January 1915 that the lives of the half a million volunteers in Lord Kitchener’s “new army” should not be “thrown away in futile enterprises” and by “this intermittent flinging … against impregnable positions”.

He separately warned, just days after Christmas 1914, when the war was supposed to have ended, of an “eternal stalemate” following months of fighting – a fear that was all but realised in the years of grim conflict on the western front.

Historians have not always acknowledged that those who prosecuted the war realised its peculiar nature at the time. But as early as January 1915, Lloyd George warned that it was to be fought by a British “citien army” facing slaughter on an industrial scale. “After three or four months of the most tenacious fighting, involving very heavy losses, the French have not at any one point on the line gained a couple of miles. Would the throwing of an additional half a million men on this front make any real difference?” he asked.

By November 1914, three months of bloody warfare across France and Belgium had settled into a complete deadlock. A continuous 600 mile network of frontline trenches had developed, running from the North Sea to the Swiss frontier, as both sides dug into impregnable positions that repeatedly proved impossible to capture by sheer weight of numbers.

‘Your Country Needs You’ first world war recruiting poster, featuring Lord Kitchener Photograph: Hulton Getty/Getty Photograph: Hulton Getty/Getty

“If our army on the Continent was to be thrown away and shattered in an operation which appeared to him impossible, the war might continue indefinitely, at any rate for two or three years more. Was it impossible, he asked, to get at the enemy from another direction, and to strike a blow that would end the war once and for all,” the secret minutes of the war council held on 8 January 1915, recorded Lloyd George, who was then chancellor of the exchequer in Herbert Asquith’s government.

It was a view which he had developed in some detail in a lengthy memorandum, The War – Suggestions as to the Military Position – for the cabinet’s committee on imperial defence.

In the past Britain’s imperial wars had largely been fought by those drawn from the rootless underworld of the Victorian slums, but for the first time those fighting at the front would have direct family ties with nearly every city, town and village across the country. In that sense it was to be the first “total war” of the 20th century.

“It is a force of a totally different character from any which has hitherto left these shores,” argued Lloyd George.

“It has been drawn almost exclusively from the better class of artisan, the upper and the lower middle classes. In intelligence, education and character it is vastly superior to any army ever raised in this country, and it has been drawn not from the ranks of those who have generally cut themselves off from home and about whose fate there is therefore, not the same anxiety at home, the people of this country will take an intimate personal interest in its fate of a kind they have never displayed before in our military expeditions.

David Lloyd George speaking in Nottinghamshire in 1915. Photograph: Hulton-Deutsch Collection/Corbis Photograph: Hulton-Deutsch Collection/Corbis

“So that if this superb army is thrown away upon futile enterprises, such as those we have witnessed during the last few weeks, the country will be uncontrollably indignant at the lack of provision and intelligence shown in our plans. I may add that operations such as those we have witnessed during the past few months will inevitably destroy the morale of the best of troops. Good soldiers will face any dangers and endure any hardships which promise ultimate progress but this intermittent flinging themselves against impregnable positions breaks the stoutest hearts in the end.”

Lloyd George added: “To force the line would require at least three to one; our reinforcements would not guarantee two to one, or anything approaching such predominance. Is it not therefore better that we should recognise the impossibility of this particular task?” he asked his war cabinet colleagues and the military chiefs.

He nevertheless believed in “the necessity of winning a definite victory somewhere”, arguing that there was a real danger that the people of Britain and France would “sooner or later get tired of long casualty lists explained by monotonous and rather banal telegrams from headquarters about ‘heavy cannonades’, ‘making little progress’ at certain points, ‘recovering trenches’ the loss of which has never been reported, etc. with the net result that we have not advanced a yard after weeks of heavy fighting.”

At that time Lloyd George proposed using Kitchener’s new army to send an advance force to Salonika [Thessaloniki] to attack Austria with the Serbs, the Romanians and the Greeks, and to plan a second operation against Turkey: “I can see nothing but an eternal stalemate on any other lines,” he warned.

Cabinet Office document detailing comparative strengths of English, French and German forces in France and Flanders in December 1914. Photograph: Guim

The alternative was to meet the demand made four days previously by Field Marshal Sir John French, the commander-in-chief of the British Expeditionary Force, that 50 – the bulk – of Kitchener’s new army battalions be sent to France. In opposing French, Lloyd George was backing Kitchener, the secretary of state for war, who felt that no more troops should remain on the western front than was necessary to hold the line and that other theatres of war should be considered.

French had tried to appeal over Kitchener’s head to Asquith, and in his secret war council memo dated 3 January made his case with a relentless numerical logic that was to be repeated for a further three years.

French argued that on the western front the figures showed “a superiority in favour of the Allies over the German forces of 1,172 guns, 500,000 effective rifles, and 65 regiments of cavalry”. He estimated on the eastern front that the Russians had 2,200 guns, 30,000 effective rifles, 18 regiments of cavalry, and 500 squadrons of Cossacks over and above the combined forces of Germans and Austrians.

“It is well known that at least a million trained Russian troops are lying close behind their fighting line, ready to reinforce as soon as arms and ammunition arrive,” he added – optimistically, given that the War Office realised the Russians’ lack of rifles meant these troops could not be used against the enemy.

Another War Office document comparing strengths of the warring field armies. Photograph: PR

But what concerned French was that despite having suffered an estimated one and a half million casualties, the Germans had a further 800,000 men in training – enough by March or April 1915 to “wipe out their existing inferiority and even once again make themselves superior to us… It seems therefore, of the utmost importance that we should take the offensive and strike at the earliest possible moment with all our available strength,” the field marshal argued.

His case rested on detailed accounting tables drawn up by the intelligence department of the War Office of the “relative strengths of the belligerent forces”.

One such War Office paper for that January 1915 meeting assumed that the Germans would not run short of men for a further three months, even with “a wastage rate of 300,000 a month”. But, in a disturbing sign of the quality of decision making, a separate War Office table estimating the strengths of the opposing armies came to almost the opposite conclusion to French’s and gave the German armies a total superiority over the Allies of nearly one million.

Kitchener told the war council that French’s demand for an earliest possible strike was simply impossible: “An advance could only be made by means of developing a tremendous volume of artillery fire, and the ammunition for this was simply not available.”

The Dardanelles today. The cabinet was eventually persuaded to back Churchill’s plan for landings at Gallipoli on the Dardenelles to open the way to an attack on the Turkish capital of Constantinople. Photograph: Burak Kara/Getty Images Photograph: Burak Kara/Getty Images

In the event Kitchener’s strong opposition meant that it was agreed to examine the possibilities of the new armies being used in other theatres of war, especially against Germany’s ally, Turkey. Kitchener was keen on an invasion of the Turkish city of Alexandretta, now Iskenderun, using the new British troops along with Australian, New Zealand and Indian formations. Instead, Asquith’s cabinet and Kitchener were eventually persuaded to back the plan put forward by the then first lord of the admiralty, Winston Churchill, for landings at Gallipoli on the Dardenelles to open the way to an attack on the Turkish capital of Constantinople, now Istanbul.

This was however to prove even more disastrous.

‘Devices that might possibly prove useful’ to end deadlock on western front

Maurice Hankey, the longserving secretary to the committee of imperial defence, on 28 December 1914 proposed to use modern science to break the already apparent deadlock in France. He argued that such impasses had been broken in past wars by the development of special materials such as Greek fire, battering rams, catapults, and siege trains.

The first of his five suggested “devices that might possibly prove useful” against German trenches was the first official reference, in all but name, to a tank in the cabinet papers. A “landships committee” was set up the following month to develop the idea while the others went through field trials under the auspices of the “inventions committee”.

“(a) Numbers of large heavy rollers themselves bullet proof, propelled from behind by motor engines, geared very low, and the driving wheels fitted with ‘caterpillar’ driving gear to grip the ground, the driver’s seat armoured, and with a Maxim gun fitted. The object of this device would be to roll down the barbed wire by sheer weight, to give some cover to men creeping up behind, and to support the advance with machine-gun fire.

(b) Bullet-proof shields or armour. Sir Edward Henry has a most interesting bullet-proof shield designed after the Sydney Street affair. The War Office, however, consider it too cumbersome for use in the field. Possibly some similar, but less cumbersome, contrivance might be designed for use where the trenches are, as at present, only a few yards apart.

(c) Smoke balls, to be massed in the trenches before an advance, and to be used if the wind is in a favourable quarter. They would be thrown by the troops towards the enemy’s trenches to screen the advancing troops.

(d) Rockets throwing a rope with a grapnel attached, which are being used by the French to grip the barbed wire, which is then hauled in by the troops in the trench from which the rocket is thrown.

(e) Spring catapults, or special pumping apparatus to throw oil or petrol into the enemy’s trenches. Sir John French (in his remarks on the recent experiments with burning oil) has asked if some such apparatus could be designed. It will be remembered that in one of their most recent official communiques the French reported that their troops had been burnt out of their trenches.”