Sainsbury's, associated with higher prices and better quality than Tesco and Asda, revealed a 13% increase in pre-tax profits during the first six months of 2008 - the retailer has now delivered 15 quarters of consecutive underlying sales growth.

"Getting the best value for money is even more important to consumers when household budgets are stretched," commented Justin King, chief executive of Sainsbury's. King said buying patterns have dramatically changed in recent months. He felt that the introduction of ranges such as "Basics" which allows shoppers to spend less if necessary, and promotions such as "Feed Your Family for a Fiver" had given it an edge over the competition.

A big marketing push behind its own-brand goods have helped it to take customers from rivals Marks & Spencer and Waitrose. King admitted that the retailer had been having "challenging conversations" with its suppliers about pricing, particularly over own-brand goods, but stressed that relations were good and denied the retailer was putting the squeeze on any companies.

About 30% of Sainsbury's food offering were on promotion, up from 25% this time last year and in line with rivals.