The waters around the British Isles are among the most dangerous in the world in terms of shipping accidents, according to conservation group WWF.

There were 135 reported accidents in the shipping lanes around the British Isles, North Sea and Bay of Biscay between 1999 and 2011, WWF said.

This made the area the fourth worst in the world for accidents, with incidents including fires, collisions and leakage of toxic waste.

WWF said the North Sea was one of the most intensively sailed seas in the world, with more than 120,000 ship movements taking place there every year.

The South China Sea and East Indies, east Mediterranean and Black Sea, were also found to be dangerous hotspots for accidents involving ships.

WWF's marine manager Dr Simon Walmsley said: "Shipping lanes around the UK are already some of the world's busiest and will get busier as the global fleet expands. The risk of accidents and environmental disaster is only going to increase, so efforts must be made to lower the risk."

WWF said fishing vessels accounted for nearly a quarter of the vessels lost at sea but cargo ships accounted for more than 40%.