In a highly critical submission to the current inquiry into the grocery market, the New Economics Foundation warned Britain was in danger of becoming a "one supermarket state" because of the commission's refusal to use its powers.

"We have to reserve judgment slightly but I have the disturbing sense of groundhog day about this inquiry," said the NEF's policy director, Andrew Simms. "It is dangerously close to being a rerun of the last inquiry into the supermarkets in 2000 when dozens of anti-competitive practices were highlighted but there were no effective remedies. If the commission can't do its job and put in place checks and balances that could ensure genuinely open markets, people will be justified in questioning exactly what the commission is for."

The NEF said the commission was "ignoring clear evidence" of the anti-competitive grocery market and failing to take account of the real wants of the consumer. It said a single supermarket chain should be restricted to 25% of the national market and a third of a local market.

It also ridiculed Tesco's attempt, in its submission to the inquiry, to define "local" as 30 minutes' drive away. It would mean that for someone living in Chelmsford in Essex, a store 17 miles away in Romford or Leigh-on-Sea would count as local.