Chemists at Plymouth University have identified the sticky substance that has killed hundreds of sea birds off the Devon and Dorset coast.
Their findings suggest it's a form of Poly Isol Butene, or PIB, used as a lubricating additive in oils to improve performance.
Tamsin Eames reports:
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Despite the rain, over a thousand people turned out to watch the annual Cheese Rolling races at Brockworth in Gloucester this lunchtime.
Philippa has the forecast for Devon, Cornwall, Somerset and Dorset
Philippa has the forecast for Bristol, Wiltshire, Gloucestershire, Somerset and Dorset.