The Energy Advice Line has joined the chorus of energy experts warning that household and business energy prices could be about to rise, driven partly by the Brexit vote.
Julian Morgan, managing director of the price comparison, switching and advice service for energy users, said the Co-op had already advised that it would be raising bills by between 3% and 6% from October 1 - representing an increase up to £70.
"Not only has the wholesale price of gas risen steadily over the past three months, but the value of sterling has fallen against the euro, representing a double whammy for British consumers," Mr Morgan said.
"This means thast as well as the wholesale price of energy rising, imports are 10% high still due to currency fluctuations.
"The Co-op has signaled that the average bill for dual-fuel customers on a standard plan will rise from £1,152 to £1,184 a year, while people with pre-payment meters could find their bills rising from £1,115 to £1,184.
"This is worrying and could be a sign that other suppliers are about to follow suit."
Independent energy consultant Cornwall Energy has confirmed that changes in the exchange rate since Brexit had made power more expensive in Britain. Gas imported from other European countries was used for household energy suppliers and for burning in power stations to produce electricity, it explained.
Mr Morgan said this meant that suppliers, especially smaller companies unable to buy their energy as far ahead as the Big Six, would inevitably pass on these extra costs to consumers.
"The only thing consumers can do is to fight back and switch suppliers," Mr Morgan said. "Despite the overall upward trend, good deals are still available, even as we head into winter. It's crucial that consumers shop around - ideally come to us for advice about the best deals available."
Even without the upward pressure on energy bills, Mr Morgan said, the Competition and Markets Authority recently concuded that customers who stayed on the most expensive standard tariffs were collectively wasting as much as £1.7 billion a year.
"It makes complete sense to regularly switch supplier and seek out the good deals elsewhere, regardless of what's happening to wholesale energy prices and the exchange rate," Mr Morgan said.
The Energy Advice Line is one of the UK's leading price comparison and switching services for business and domestic energy customers. It is also an advocate for energy reform and has campaigned for a better deal for energy users, uncluding calling for a ban on cold calling and changes to regulations to make it easier for all consumers to switch suppliers.
The service is completely independent and free. Consumers can quickly and simply search the market for the best available energy deals from an extensive panel of small and large energy suppliers. THe service also offers a free advice line for business energy customers.
For further information visit energyadviceline.org.uk