Subway, the fast-growing US sandwich chain, is to trial concessions in three Tesco stores in a move the company hopes will drive forward its plans of opening 2,010 sites by 2010. The company, which already has concessions in 24 forecourt and convenience stores operated by BP and Spar in the UK, will trial sites next month in three of the supermarket chain’s Express stores in the Midlands and south of England. Subway is currently rolling out 1,000 concessions with Wal Mart in the US, and plans to open 400 in grocery outlets in the UK over the next four years. It currently operates 746 outlets in the UK.