Support for a grocery industry regulator is growing, with an alliance of trade bodies backing the concept in a written submission to the Competition Commission's probe into the sector.

The Rural Shops Alliance has joined with the National Federation of Retail Newsagents, the Local Works campaign and Booker to produce the paper. Professor Alan Hallsworth, reader in retail management at Surrey University, is helping to compile it.

"We're going to agree with others to support the idea of appointing an industry ombudsman, originally proposed by the All Party Parliamentary Small Shops Group," he said. "We believe there is a groundswell of opinion in favour of such a regulator or adjudicator."

He previously produced reports for the Association of Convenience Stores arguing that the OFT definition of the market was blinkered. He championed a single market definition and maintained the largest supermarkets dominated the supply chain.

Hallsworth said the big theme of the submission would be convenience. "There is a strong emphasis on price in this investigation, but it's convenience, not price that matters to most people. As attrition from the big guys increases and local shops disappear, so does convenience."

Meanwhile, Sainsbury's chief executive Justin King said it had a "fair and engaged" meeting with the Commission last week.