The output in Britain was limited by labour shortages due to the manpower demand of the armed forces and a rocketing national debt.

[citation needed] When the United States of America declared war on Germany on 6 April 1917, many in Britain hoped this event would solve all these problems.

The two men directly responsible for British tank production, Eustace Tennyson d'Eyncourt and Lieutenant-Colonel Albert Gerald Stern, initially considered sending a delegation to the United States immediately, to convince the new ally to start production of a British tank design.

It was designed with existing British industrial capacity in mind, posing limits that might be overcome by larger American production facilities.

The Navy was on the brink of sending a team of engineers to Britain when the American Department of War was informed of developments by the US Military Attaché in London.

It ordered the project to be shifted to the Army and selected Major H. W. Alden – in peacetime he had been an industrial expert – to go to the UK to work with the Mechanical Warfare Department design team at Dollis Hill on the first drawings of the new tank.

[3] Stern was appointed in September to the new position of "Commissioner for Mechanical Warfare (Overseas and Allies Branch)" in order to coordinate tank production with the US and France.

[3] Stern went to France to meet the French Minister of Munitions, Louis Loucheur and the American commander-in-chief, John Pershing.

This came as no surprise to Stern who had already prepared an "International Plan" of ten points (in fact a bilateral agreement between the US and Britain) that he now managed to get accepted by the Americans.

Its main points included (using the original terminology): The plan already contained a specification: the tank should have a 300 hp (220 kW) engine, weigh 38.8 tons[citation needed] (39.5 tonnes) and have a trench crossing capacity of 14 feet (4.3 m).

It was made into a formal treaty signed by the British Foreign Secretary Arthur Balfour and the US Ambassador Walter Hines Page on 19 January 1918.

But it also resembled the Mark VI-project in that it had more rounded and wider tracks and a large superstructure on top directly beneath the front of which the driver was seated.

This vastly improved fighting conditions as a bulkhead protected the crew against the deafening engine noise, noxious fumes and heat.

Major Alden had designed the sponsons to be retractable (they could be swung in at the rear by the crew, being pivoted at the front), to reduce the width of the vehicle if enemy obstacles were encountered.

The tank carried 208 shells and 13,848 machine gun rounds, mostly in a large ammunition locker in the centre which formed a platform on which the commander stood behind the driver observing the battlefield through a cupola with four vision slits.

The twelfth crew member was the mechanic, seated next to the 300 hp Liberty V-12 (or in British tanks Ricardo V-12) petrol engine) cooled by a large horizontal radiator.

In absolute terms the vehicle was very large: at 10 ft 3 in (3.12 m) tall the Mark VIII was the second largest operational tank in history, after the Char 2C.

The roof and bottom of the hull were protected by only 6 mm thick armour plate, leaving the tank very vulnerable to mortar shells and landmines.

However, suffering from a lack of manpower and raw materials the French were not forthcoming in providing any facilities for the production of the International Tank.

Soon the Americans decided to build a brand new assembly factory at Neuvy-Pailloux 200 miles south of Paris, contracting a British company.

[6] On arrival it transpired that no mass-produced parts were ready to finish the prototype, so the Locomobile Automobile Company in Bridgeport, Connecticut made these all by hand, completing the first vehicle on the 28 September.

During 1918, the then prevalent preoccupation with trench crossing capabilities led to preparations being made for the production of an even longer tank: the Mark VIII* (Star).

[1] The tank appearing in the 1989 Indiana Jones and the Last Crusade movie was a replica vehicle made from an excavator, following the hull shape of the Mark VIII but with a turret added.