The levies MasterCard imposes on retailers are a “tax on consumers” and should be cut, the Office of Fair Trading has said.

Following a five-and-a-half year investigation, the OFT has said that retailers have been charged at least £100m too much a year for almost five years.

The BRC welcomed the findings. BRC director general, Kevin Hawkins, said: “The cost of these practices to the consumer in higher prices is conservatively estimated at £500m. Retailers will be considering their position regarding a possible appeal on this issue.”