Hemp is used to make a lightweight, insulating concrete that will form the walls of the house

But never before has the class B drug been described as a way to save the environment too.

Researchers at BRE Centre for Innovative Construction Materials believe they have discovered a way to build carbon-neutral homes of the future - by using cannabis instead of the usual bricks and mortar.

Experts are working on a revolutionary housing project - delivered by the National Non-Food Crops Centre (NNFCC) - using construction materials made out of hemp-lime, a form of the drug.

The lightweight building material is made of fibres from the fast-growing cannabis plant, bound together using a lime-based adhesive.

The hemp plant stores carbon as it grows and combined with the low carbon footprint of lime and its efficient insulating properties, gives the material a “better than zero carbon” footprint, researchers said.