Retailers have claimed they will be hit with £3.5m in additional red tape under plans by the FSA to make its Food Hygiene Rating system mandatory across the UK.

The agency has launched a consultation document to determine the “economic, social and environmental” impact of toughening its existing voluntary scheme.

Plans include not only making it compulsory for retailers to display ratings, but also forcing them to pay for the cost of any re-inspections after improvements have been carried out.

The move comes after food hygiene ratings compiled for The Grocer found Tesco, Asda, and The Co-operative Group had been told food hygiene in their stores must improve after inspections within the last two months.

The figures, compiled by Transparency Data, revealed that since 1 September, 8% of the 50 inspections carried out in Tesco stores received a score of two out of five, which means “improvement necessary”. Out of 88 inspections at Co-op Group stores, 5.7% scored either a one or a two, while Asda was told to improve hygiene in one store out of 16 that were inspected.

In August, The Grocer found that independents fared far worse, with 17.1% scoring a score of two or lower since January 2011.

Retail leaders admitted very few stores display their scores, but said the plans for a mandatory scheme are unnecessary and fly in the face of government pledges to slash red tape.

A similar impact assessment carried out in Wales resulted in plans for a mandatory scheme due to come in next year, with an estimated £250,000 cost to businesses. FSA Scotland, which has its own remit, is working with the FSA on the mandatory scheme.

“There are currently successful voluntary food hygiene schemes all across the UK,” said ACS CEO James Lowman. “The introduction of a mandatory scheme would only serve to burden retailers and could cost the sector around £3.5m if the same regulations are applied as in Wales.”

BRC director of food Andrew Opie added: “The FSA has been unable to produce any evidence that making this system mandatory will prevent food safety breaches. All leading retailers already have very stringent hygiene standards and if inspectors find that and store has unsafe hygiene standards we believe they should close them down and take action, rather than enforce unnecessary red tape and costs across the entire industry.”

An FSA spokeswoman stressed it would ” work with businesses and other stakeholders”.