Coffee chains trial fully compostable cup and lid

A fully compostable and recyclable coffee cup and lid is being tested by major high street coffee chains.

The company behind the cup, which uses a revolutionary type of 'bioplastic', describes it as a "world first".

It says the plastic, which uses eucalyptus, means the cup can withstand heat better than other types of bioplastic.

Yet within three months on a compost heap, both the cup and the lid break down to leave just carbon dioxide and water.

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The inventors also claim that because the plastic is wood-based the whole thing can be recycled with paper.

Paul Mines, chief executive of Biome Bioplastics, told Sky News: "What we've got here is a world first.

"It's a bioderived coffee cup and lid. So the cup is made from paper outer and bioplastic inner and then the lid is made from a bioplastic taken from trees.

"Now, put these items together and you can put them either into the paper waste stream or they can compost in the food waste stream."

Working alongside scientists at the Green Chemistry department at the University of York, the company is now working on a new straw-based plastic.

Research fellow Dr Thomas Farmer told Sky News: "We're trying to think about using a sustainable feedstock which will always be there for future generations to use, unlike oil... I think it's going to eventually allow us to produce plastics with significantly reduced impact on the environment."

But many scientists are sceptical about bioplastics.

The specific compost conditions required for them to break down include being subjected to temperatures of 50-60 degrees Celsius, as well as contact with soil and water. So they wouldn't break down in landfill or sea water.

Dr Arturo Castillo, a research fellow at the Centre for Environmental Policy at Imperial College, said: "Typically the conditions that you have in composting tanks are not what you have in the sea, which means really that having biodegradable plastics that are meant to be composted are not really going to be the main solution."

"There's no silver bullet to solve this problem and really what we need to do is to try to stop the waste from getting into the ocean in the first place."