During August and September 1914, armoured cars had been employed with considerable success in Belgium and north-western France. This no doubt brought with it the revival of the idea. Be this as it may, in October of this year Lieutenant-Colonel (now Major-General) E. D. Swinton put forward a suggestion for the construction of an armoured car on the Holt tractor or a similar caterpillar system, capable of crushing down wire entanglements and crossing trenches.
At the same time, Captain T. G. Tulloch, manager of the Chilworth Powder Company, was also devoting his attention to the possibility of constructing a land cruiser sufficiently armoured to enable it to penetrate right up to the enemy’s gun and howitzer positions. In November the idea was communicated by Captain Tulloch to Lieutenant-Colonel Swinton and to Lieutenant-Colonel (now Colonel Sir Maurice) Hankey, Secretary to the “Committee of Imperial Defence,” and later on to Mr. Churchill, then First Lord of the Admiralty, who, in January 1915, wrote his now historic letter to Mr. Asquith:
“My Dear Prime Minister,
“I entirely agree with Colonel Hankey’s remarks on the subject of special mechanical devices for taking trenches. It is extraordinary that the Army in the field and the War Office should have allowed nearly three months of warfare to progress without addressing their minds to its special problems.
“The present war has revolutionised all military theories about the field of fire. The power of the rifle is so great that 100 yards is held sufficient to stop any rush, and in order to avoid the severity of the artillery fire, trenches are often dug on the reverse slope of positions, or a short distance in the rear of villages, woods, or other obstacles. The consequence is that the war has become a short-range instead of a long-range war as was expected, and opposing trenches get ever closer together, for mutual safety from each other’s artillery fire.
“The question to be solved is not, therefore, the long attack over a carefully prepared glacis of former times, but the actual getting across 100 or 200 yards of open space and wire entanglements. All this was apparent more than two months ago, but no steps have been taken and no preparations made.
“It would be quite easy in a short time to fit up a number of steam tractors with small armoured shelters, in which men and machine-guns could be placed, which would be bullet-proof. Used at night they would not be affected by artillery fire to any extent. The caterpillar system would enable trenches to be crossed quite easily, and the weight of the machine would destroy all wire entanglements.
“Forty or fifty of these engines, prepared secretly and brought into positions at nightfall, could advance quite certainly into the enemy’s trenches, smashing away all the obstructions and sweeping the trenches with their machine-gun fire, and with grenades thrown out of the top. They would then make so many points d’appui for the British supporting infantry to rush forward and rally on them. They can then move forward to attack the second line of trenches.
“The cost would be small. If the experiment did not answer, what harm would be done? An obvious measure of prudence would have been to have started something like this two months ago. It should certainly be done now.
“The shield is another obvious experiment which should have been made on a considerable scale. What does it matter which is the best pattern? A large number should have been made of various patterns; some to carry, some to wear, some to wheel. If the mud now prevents the working of shields or traction engines, the first frost would render them fully effective. With a view to this I ordered a month ago twenty shields on wheels, to be made on the best design the Naval Air Service could devise. These will be ready shortly, and can, if need be, be used for experimental purposes.
“A third device, which should be used systematically and on a large scale, is smoke artificially produced. It is possible to make small smoke barrels which, on being lighted, generate a great volume of dense black smoke, which could be turned off or on at will. There are other matters closely connected with this to which I have already drawn your attention, but which are of so secret a character, that I do not put them down on paper.
“One of the most serious dangers that we are exposed to is the possibility that the Germans are acting and preparing all these surprises, and that we may at any time find ourselves exposed to some entirely new form of attack. A committee of engineering officers and other experts ought to be sitting continually at the War Office to formulate schemes and examine suggestions, and I would repeat that it is not possible in most cases to have lengthy experiments beforehand.
“If the devices are to be ready by the time they are required it is indispensable that manufacture should proceed simultaneously with experiments. The worst that can happen is that a comparatively small sum of money is wasted.
“Yours, etc.”
At about the time that the above letter was written, Lieutenant-Colonel Swinton again brought the matter forward and urged the desirability of action being taken, but as it was stated that the design and building of Captain Tulloch’s machine would take a year to complete it appears that this led to the proposals being shelved for the time being.
On June 1, 1915, Lieutenant-Colonel Swinton, who had then returned to France, submitted an official memorandum on the above subject to G.H.Q., which was passed to Major-General G. H. Fowke, Engineer-in-Chief, for his expert opinion. This memorandum may be summarised as follows:
The main German offensive was taking place in Russia; consequently, in order to attain a maximum strength in the east, it was incumbent on the Germans to maintain a minimum one in the west; and, in order to meet the shortage of men on the Western Front, the Germans were mainly basing their defence on the machine-gun.
The problem, consequently, was one of how to overcome the German machine-gunners. There were two solutions to this problem:
(i) Sufficient artillery to blast a way through the enemy’s lines.
(ii) The introduction of armoured machine-gun destroyers.