A number of utilities providers have failed to come out favourably following a Which? investigation.

The consumer group called the six major energy suppliers 12 times in one week, to find that many were offering questionable advice to their customers.

Although they were asked to provide the cheapest energy deal, nearly a third of the calls did not result in this information being provided.

Incorrect information was also given relating to cashback deals, potential savings and fixed prices.

Richard Lloyd, Which? executive director, said: "Giving the right advice to customers about switching matters more than ever when so many people are struggling with escalating fuel bills and colder weather is starting to bite."

He recommended that customers ask their supplier about exit fees, paying by direct debit and managing their account online in order to receive a discount on their utilities.

Switching to another supplier could also help save money, added the expert.