The Association of Convenience Stores (ACS) has turned up the heat on the Office of Fair Trading (OFT) in its efforts to persuade it to refer the grocery market to the Competition Commission by submitting new research into pricing in Tesco’s One Stop stores.

The research, based on price comparisons across a range of products, shows that One Stop stores charge more than a quarter more than larger Tesco stores and 20% more than Express stores.

The ACS has submitted its findings to the OFT in a bid to show that the Office’s claim that consolidation in the grocery market has benefited consumers is incorrect.

ACS chief executive David Rae said: “Our research shows that Tesco is not passing on the benefits of its enormous buying power and economies of scale to the consumer. If the OFT has not undertaken proper price comparisons then its conclusions on the grocery market must be thrown into doubt.”

Research carried out by C-Store in 2003 found that One Stop stores were 14% more expensive than Express stores.