Every year, approximately 15,000 Dall's porpoises are killed in the seas off Japan, in a harpoon hunt repeatedly described by the International Whaling Commission as "clearly unsustainable".

Once landed, the catch is processed and sold throughout the supermarkets and fish markets of Japan, often illegally mislabelled as "whale meat" to increase its value tenfold.

It is even distributed to some Japanese schools as part of the obligatory school lunch programme.

But campaigners say it's not only putting the species at risk, it's also affecting the health of humans.

Charlie Angela reports from London.

12 March 2010