Why have thousands of lobsters, crabs and other forms of marine life been mysteriously dying along the north east coast of England?
Fishermen have long argued that toxic chemicals are to blame – but the government has steadfastly ruled that out.
This programme can reveal new evidence that indicates those deaths could be linked to pollution caused by the dredging of the River Tees.
Correspondent: Alex Thomson
Producer: Nanette van der Laan
Camera and editor: Alastair Thomson