The ban on collecting cockles along the coast of south west Wales has been re-introduced less than a month after it had been lifted.

Swansea and Carmarthenshire councils have imposed the ban once again, affecting the Burry Inlet at Penclawdd, because of toxins found in the cockles.

Diarrhetic Shellfish Poisoning

A gastrointestinal illness Symptoms - diarrhoea, vomiting and nausea First case - Netherlands 1960s No fatal cases reported Complete recovery within three days In 1981 there were over 5000 cases of DSP reported in Spain

A 10-month ban was lifted in May after results of samples taken over a two week period from both sides of the estuary were toxin-free.

The lifting of the ban came just a day after cocklers staged a protest at Penclawdd, maintaining the shellfish were safe to eat.

The collecting ban was imposed last July by the local authorities after the Food Standards Agency (FSA) found Diarrhetic Shellfish Poisoning (DSP) during routine sampling.

Carmarthenshire council's head of public protection Philip Davies said: "The DSP toxin has reappeared.

"This leaves us with no choice but to place a ban on shellfish gathering in the area. "

The cocklers have called on the FSA to change its method of testing on mice to using chemicals instead.

Cockle-pickers fear industry crisis

They claim chemical testing would provide more accurate results.

The fisheries of the Burry Inlet provide a quarter of all British cockles.

The shellfish are gathered by hand picking - a technique used since Roman times.

Cocklers fear the prohibition of harvesting could lead to a crisis in the industry as the cockle beds become overpopulated.

If the young cockles do not have enough space to grow their shells will burst. Mussels, which feed off the shells, will then take over.

The local authorities say the ban will again be lifted once the tests for dioxins prove negative.