Which? finds 80 per cent of energy switchers don't pick out the best deals

More than four in five people in Britain who switched energy supplier last year did not pick out the cheapest new provider.

Research by the consumer group Which? shows that fewer than 20 per cent of switchers maximised savings on energy bills, and thousands were misled by internet comparison sites that do not cover the whole market.

Which? provides the UK's only independent, not-for-profit energy price comparison service, www.switchwithwhich.co.uk. However, most people who switch provider use commercial sites, some of which do not show a full range of alternative suppliers, or which give undue prominence to a company as a result of a commercial arrangement.

Eleanor Barnes of Which? said: "It is vital that internet comparison sites show all available price tariffs so that consumers can choose the best one available. For example, they should not be excluding tariffs on the basis of payment method.

"Which? advises consumers to check carefully the comparisons they are presented with and to make sure that they understand the deals that are on offer and what they are choosing. People on average save £245 by using switchwithwhich.co.uk, which prides itself on being a truly impartial service and enabling consumers to compare and switch between all major UK direct suppliers and all tariffs."

About half UK homes have switched energy supplier since the market was deregulated in the 1990s. Although several utility companies have been fined in the past decade for mis-selling, Which? said its research (by the Economic & Social Research Council) found no direct evidence that consumers made worse decisions when a sales agent was involved.

The consumer group said it believed some people had resisted switching due to "misplaced brand loyalty" which "generally goes unrewarded".

The report follows research published by the University of Warwick, which claimed that the UK electricity market is still not fully competitive.