Cultivator No. 6

Cultivator No. 6 was the code name of a military trench-digging machine developed by the British Royal Navy at the beginning of World War II. The machine was originally known as White Rabbit Number Six; this code name was never officially recognised, but it was said to be derived from Churchill’s metaphorical ability to pull ideas out of a hat. The codename was changed to the less suggestive Cultivator Number Six to conceal its identity. The name was later changed to N.L.E. Tractors. Winston Churchill sometimes referred to the machine as his mole and the prototype machine was dubbed Nellie. It was lightly armoured and carried no weapons. It was designed to advance upon an enemy position largely below ground level in a trench that it was itself excavating. On reaching the enemy's front line, it would serve as a ramp for the troops, and possibly tanks, following in its trench.

Cultivator No. 6 was an enormous machine and was planned to be built in substantial numbers. The overall weight was 130 tons and the length was 77 feet 6 inches (23.62 m). The machine's development and production was enthusiastically backed by Winston Churchill and work on it continued well past the point when there was no obvious use for it. In the end, only a small number of machines were constructed and none were used in combat. In his memoirs, Churchill, said about it: "I am responsible but impenitent".