Panjandrum

The delivery method for such a quantity of explosives posed a significant problem, and one of the concepts discussed ultimately resulted in the construction of the prototype "Great Panjandrum".

The designers predicted that, with a full 4,000-pound (1,800 kg) load, Panjandrum would achieve speeds of around 60 mph (100 km/h), with enough momentum to simply crash through any obstacles between its launch point and target.

Since nothing remotely resembling the Panjandrum had ever been constructed before, the trials began with trepidation—only a handful of cordite rockets were attached to the wheels, and the payload was simulated by an equivalent weight of sand.

More weeks were spent testing every conceivable variable from thicker cables to heavier rocket-clamps without success before the DMWD received notification that the weapon was only required to be consistently able to travel in the general direction of the enemy.

It hit a line of small craters in the sand and began to turn to starboard, careering towards Klemantaski, who, viewing events through a telescopic lens, misjudged the distance and continued filming.

Panjandrum was now heading back to the sea but crashed on to the sand where it disintegrated in violent explosions, rockets tearing across the beach at great speed.

However, it has since been suggested that the entire project was a hoax devised as part of Operation Fortitude, to convince the Germans that plans were being developed to attack the heavily fortified defences surrounding the Pas-de-Calais rather than the less-defended Normandy coastline.