A million plastic bottles are bought around the world every minute and the number will jump another 20% by 2021, creating an environmental crisis some campaigners predict will be as serious as climate change.

Between 5m and 13m tonnes of plastic leaks into the world’s oceans each year to be ingested by sea birds, fish and other organisms, and by 2050 the ocean will contain more plastic by weight than fish, according to research by the Ellen MacArthur Foundation.