The same month Lieutenant Kenneth Symes began to test 2 inch (51 mm) armour plate by firing at it with various captured German guns.

In June, this programme was expanded by testing several types of plate at Shoeburyness, delivered by armour producer William Beardmore and Company.

The preliminary design, for which partial blueprints are in the Albert Stern archive at King's College London, featured two six-pounders in sponsons either side of a bulbous nose equipped with no fewer than five machine guns.

Where the nickname 'Flying Elephant' came from no one knows for sure, though it was probably the result of the trunk-like nose gun, domed front, and enormous bulk combined with a traditional British lightheartedness.

Albert Gerald Stern, the head of the Tank Supply Department, wrote that the War Office ordered the end of the project late in 1916, because it deemed mobility more important than protection.

[4] Historian David Fletcher speculated that the project ran into trouble because the vehicle was grossly underpowered; top speed was estimated at two miles per hour, and it seems unlikely that it could have worked itself free when stuck in mud.

However, John Glanfield writes that Tritton, in an effort to lighten the machine and make it more practicable, halved the thickness of the armour, reducing the overall weight to a still hefty 50–60 tons.