The great shark egg hunt: the charity project that's got us combing beaches

In 2003 one charity set out to raise awareness of sharks in British waters, 75,000 egg cases later it's going strong

Shark eggs. Or rather the egg cases their embryos leave behind once they have developed. Since 2003, the Shark Trust has been encouraging "citizen scientists" - their supporters - to collect and identify egg cases, commonly known as mermaid's purses, with a campaign called The Great Eggcase Hunt.