The two farms in Senegal that supply many of the UK's vegetables

Between January and March, if you browse the fresh produce aisles of the UK's biggest food retailers, including Tesco, Sainsbury's, Asda, Aldi and Lidl, you're likely to see spring onions, radishes, green beans, chillis, butternut squash, and cobs of corn, all labelled Produce of Senegal.