This week's mechanical migraine promises to be a Scrapheap classic. The teams must build contraptions to throw a 100-kilogramme scooter as far as they can, without the help of compressed gas or gunpowder. The Balloonatics, a trio of hot air balloonists from Liverpool, take on The Aquarium Crew, a team of aquarium constructors from Dorset.

The show’s own verdict is on its page.