The new-found enthusiasm for sweet potatoes has triggered record supermarket sales but a new variety means they are now not so exotic. British-grown sweet potatoes will go on sale in supermarkets for the first time next week, the first successful results of a crop innovation in the south of England which has taken three years to develop. The move has been hailed as a breakthrough for British farming, as the sweet potato typically relies on warm and dry growing conditions and has until now only been sourced overseas, typically from southern US states such as North and South Carolina, Egypt, Senegal and Israel. Sales at Asda are up 50% in the last year. Marks & Spencer said sales were currently “going through the roof”, up 112% year on year, while Waitrose reports a 30% year-on-year uplift. In March the ONS added them to their basket of goods to help measure inflation.