Business rates will soar by their highest rate in 20 years thanks to September’s shock inflation figures.

The government’s Retail Price Index hit 5.6% in September, meaning business rates – which are linked to the inflation calculation – will see an unprecedented rise next April.

James Lowman of the Association of Convenience Stores called on the government to help businesses cope with the extra burden.

“A business rates increase of 5.6% will simply not be affordable at a time when growth is stalled,” he said. “The government has to delay this increase or allow a one-off emergency reduction in the rate of increase.”

The average bill for a village shop of £6,000 a year would increase by more than £300, the ACS said, but high street stores and garage forecourts would face much more damaging increases.

Lowman added: “We will be working with the government to try to find ways to mitigate this potentially devastating additional cost.”