This week, two teams of four highly skilled engineers are given the implausible task of transforming two concrete mixer lorries into boats. The vessels they create need to be capable of carrying a half-tonne cargo on a figure-of-eight course around a lake. They must also build a winch system to hoist their cargo off the boat and carry it across a finish line. All in just four days! Motor Morphers’ HQ is manned by Mark and Hadrian, who have some heavy machines for cutting, drilling and hammering. Hadrian’s response to Jason’s suggestion about how the teams should proceed is, “If they turned that into a human-powered paddle steamer, they would most definitely be bonkers!” But the teams have other ideas – the Reds plan to attach some outriggers behind a hollowed-out cement drum, while the Blues, led by Ed ‘The Professor’, want to create an impeller-driven craft, a bit like a jet ski.

This week, each team has to convert a two-tonne, ten-mile-an hour milk float into a tyre smoking dragster. Leading the Red Team again is the Prince of Pressure Steve Garfirth, a specialist in hydraulic engineering. The Blues’ skipper is Ed ‘The Professor’ Rycroft, who develops performance-handling technology for a top car firm. They must use as much of the milk float’s materials as possible in their new designs, but also have a kitty of £500 for any extras they wish to bolt on. After four days of building time, their conversions will be brought to a drag-racing strip where they will take part in a head-to-head challenge. The best of three will win.

A beet harvester is similar to a combine harvester, weighing 11 tonnes and measuring seven metres in length. Its function is to pull root vegetables out of the ground. Once again, hydraulics expert Steve ‘The Prince of Pressure’ captains the Red Team with Ed ‘The Professor’ Rycroft leading the Blue. They each have to design and build a machine from parts scavenged from their harvesters, capable of destroying a building made of foot-thick, reinforced concrete walls that has stood for more than 50 years. The teams have a kitty of £500 each for extras and they have just four days to build their wrecker before being allowed half an hour each to cause as much mayhem as possible. However, when Jason explains that the teams can’t just get in the massive harvesters and drive at the building, he is met with a chorus of groans.

This week, Jason Bradbury challenges the teams to morph two post-war Green Goddess fire engines into machines capable of felling trees and chopping the trunks into logs. The two teams have four days to re-engineer a Green Goddess into a tree-chopping tyrant, and their creations will be tested in a forest on the Welsh borders, with the team that chops the most logs being crowned the winner. The Red Team are again being led by the Prince of Pressure, Steve, with Ed, The Professor, taking the reins of the Blue Team. At the chalk board, Steve outlines the Reds’ plan – they are going to bolt a manoeuvrable circular saw on to the front of the Goddess. To fell the trees the saw will be horizontal, but once the tree is down the saw will then turn to an upright position so that it can chop the trunk into logs.