Toxin levels in fish lead to calls for UK-wide ban on mercury dental fillings

Exclusive: More than 98% of fish and mussels tested in English waters contain mercury above EU safety limits

Britain is facing mounting pressure to ban mercury dental fillings, one of the few countries yet to prevent the practice, as new data reveals alarming contamination levels in the nation's fish and shellfish.

Mercury is a potent neurotoxin that can harm the nervous, digestive and immune systems, as well as the lungs, kidneys, skin and eyes, even at low levels of exposure. Its organic form, methylmercury, is particularly dangerous to unborn babies and can move through the food chain building up in insects, fish and birds.