Natalie Hitchins, Which? Head of Home Products and Services, said:
“Until now many customers have found themselves paying over the odds for staying with their provider after their initial contract has ended – so notifying people in advance that they may be about to be hit by these poor value rolling tariffs is a step in the right direction.
“Providers should be fighting hard to show that they deserve to hold on to their customers, not hitting them with an unexpected price hike the minute their contract is up.
“Anyone nearing the end of a contract should compare prices to see if there is a better deal available – switching suppliers could potentially save you hundreds of pounds a year.”