It is intended to be the most prestigious environmental prize in history, recognising the pioneers who will save the planet in years to come. When the Duke of Cambridge hands out his Earthshot Prize medals on Sunday, winners will no doubt be thrilled they are fully recyclable.... But they may not spot that they have also been made out of sludge. The 50 medals, inspired by the first photograph taken of the earth from the moon in 1969, are made from recycled brass sourced from tiny fragments of m