 Tesco PLC LSE:TSCO, Britains biggest retailer, forecast that significant cost inflation pressures would mean full year adjusted operating profits will be at the bottom end of guidance between 2.4 billion and 2.5bn. Delivering first half results the group, which has a 27 share of Britains grocery market said there were significant uncertainties in the external environment still exist, most notably how consumer behaviour continues to evolve. 