TV celebrity chef Hugh Fearnley-Whittingstall has described on national television how Tesco and two other national supermarkets are purchasing prawns from CP Foods (owned by a Thai billionaire), which is being accused of illegal fishing for 'trash fish'.

The 'trash fish' - a mixture of young fish and sharks, crabs, starfish and even turtles - are illegally caught off Thailand's coastal waters to help feed Britain's 50,000 ton annual prawn habit.

Mr Fearnley-Whittingstall stated that this indiscriminate fishing practice was devastating to the local eco-system, as it hugely reduced the diversity of sea-life.

Tesco, the Co-op, Morrisons and the Thai prawn supplier CP all refused to be interviewed by Mr Fearnley-Whittingstall.

The supermarkets' 'trash fish' scandal follows revelations made last year about the gelatin-injecting adulteration of prawns in China. It also follows the current criminal activity of food adulteration and the resulting mislabelling of processed foods.

Our taste for prawns is killing the sea

Yesterday Tesco paid for double page advertising in the national press blaming the 'whole food industry' while refusing to take responsibility for food adulteration, its lack of auditing of its supply chain and lack of transparency with its customers. Instead Tesco stated it was 'changing' and making its supply chain 'simpler'.

Tesco stated: 'We know that all this will only work, if we open about what we do.'

This begs the question: Why is Tesco refusing to talk to the media about its prawn suppliers?

Tesco was warned four years ago by Unite about its meat supply chain, but took no action.