Farmers are warning that fertiliser prices are now so high, some fields will simply not be planted this year. Prices are currently four times what they were last January. It's due to the high cost of gas which has seen fertiliser plants in the UK and across Europe suspend production. We hear from Dame Ellen MacArthur on how farming could benefit from a circular economy. And all this week we’re looking at shellfish. Today the focus is on cockles. We visit the Gower Estuary in Swansea where cockle pickers have worked for hundreds of years. Presented by Charlotte Smith and produced by Beatrice Fenton.