Farmers and farm shops could benefit from a decision that will re-open the probe into supermarkets’ move into the corner shop sector.

The Office of Fair Trading allowed an appeal against its earlier decision not to fully investigate the multiple retailers’ expansion on competition grounds.

Robin Tapper, head of food and farming at the NFU, welcomed the news, which will give the Association of Convenience Stores a second chance to make its case.

“At last the OFT has bowed to pressure, which may be a hopeful sign for tackling retailer power in the future.

“It gives us an opportunity to rethink whether convenience stores and supermarkets are two separate sectors or just one.”

The ACS claims supermarket expansion has had a huge impact on convenience stores in urban areas, with 2000 going out of business last year.

It complains that the big stores use unfair practices, such as selling below cost, and is pushing for a full market review of the grocery sector by the Competition Commission.

A spokesman for ACS said a review could prove important for farmers and rural retailers because many stores stock local produce.

Rural shops could also be at risk as wholesalers’ shrinking market made it uneconomical to supply goods outside urban areas, he added.

The OFT has said people should not expect its decision to be overturned.

“We have not said that the decision was right or wrong, just that it was insufficiently considered,” said a spokesman.