Proposals to require supermarkets to release detailed pricing data could end up harming local shops, the Association of Convenience Stores has warned.

Labour MP John Denham’s proposals would require the 10 largest retailers in the UK to make available real time data about products and prices in every store in the country in order to improve transparency. The data made freely available could then be used by software developers to create price comparison tools for consumers.

Introducing the Supermarket Pricing Information Bill in the House of Commons, Denham said: “We want to know which supermarket genuinely has the best prices. We want to know how much extra we will pay if we go to the small branch—the local, the express—rather than a superstore of the same company.

“We want an easy way to work out the difference in cost between vegetables, some of which are bagged, some of which are loose and some of which are sold confusingly in different quantities. The truth is that no one can be sure that they are getting the best deal or the best information on any of those things today.”

But ACS chief executive James Lowman warned that the Bill could draw shoppers away from independent retailers.

 “We welcome the fact that following our intervention, John Denham has made clear that he does not intend for his proposals to impose legal requirements on small retailers forcing them to share data in this way,” he said.

“However, we remain concerned that by forcing the development of price comparison websites and mobile apps that only track the biggest retailers, the Bill could actually draw shoppers away from using their local independent stores.”