While the mill could not give us details of how exactly this is achieved, it said Icebreaker's proprietary process uses less energy than other dyeing processes.

It also says it was inspired by the Japanese denim masters to achieve deeper shades and richer casts.

A spokesperson said: “The Japanese have a rich and ancient tradition of indigo dyeing, which, coupled with post-war industrialisation, resulted in a justifiable reputation as artisans of indigo. Our methods help recreate the cast and richness that they are famous, for while dialling down the relative energy cost.”

The technology has been piloted for six months and is now ready to introduce to the market.

 

Image credit: Artistic Milliners' Instagram