Is this the beginning of trench warfare in the supermarket aisles? There has been some light sparring over the past five years against a backdrop of economic recession and falling food demand both here and in the UK. But the real battle may be just about to start.

A cutthroat pricing battle which started last year between the big supermarkets in the UK has contributed to the first annual drop in the amount people spend on food since records began in 1989.