When Sir Terry Leahy stood up in May and declared that Tesco, the UK supermarkets group of which he is chief executive, was putting local and ethical sourcing, recycling and greener energy production at the heart of its corporate culture, the retail world’s ears pricked up.

Sir Terry, delivering a speech to a room filled with green activists and local town planners at the Work Foundation in London, declared that the rules of engagement in retailing were subtly shifting.