The research, by the Royal Bank of Scotland (RBS), said a trolley of shopping now costs 5.6% more in Britain than it did a year ago. In the eurozone, the price has only increased by 1.9% in the same period.

The report, called 'The Return of Rip-Off Britain', found tea and coffee prices had increased by 10.2%, compared with a 1% rise on the continent.

Poor harvests and rising power prices can be blamed for the increases, the authors said, but they believe the dominant position of the supermarkets was behind the much bigger rise in British prices, This Is Money reported.

The Competition Commission is currently investigating the power of the supermarkets.