Millions of energy customers have been urged to switch suppliers or tariffs to save more than £400 a year before the latest round of price hikes.
The latest price hike by British Gas came into effect on May 29, increasing the bills of four million of its dual fuel standard tariff customers from £1,101 to £1,161.
The amount is £364 more per year than the cheapest deal on the market, but still only makes the British Gas standard tariff the fourth most expensive of the Big Six firms after npower, Scottish Power and SSE once all price rises have come into effect, watchdog Which? calculated.
SSE customers on its standard tariff will see the biggest price increase at an average £76 more per year from July 11.
“If British Gas prompted MPs to say these are unjustified rises, then SSE’s are even higher,” consumer journalist Georgie Frost told talkRADIO.
Energy minister Claire Perry said in April she was “disappointed” by the increase, and said the government would be introducing a price cap this winter.
Of the SSE rises, she said: "It is extremely disappointing that SSE has decided to announce this unjustified price rise - the highest yet from the Big Six - ahead of the new law coming into effect later this year.”
Listen to Georgie Frost's advice on the breakfast show above
Nine million customers will be affected by the price hikes, and Frost urged all consumers to go on comparison websites to scout out better deals.
Scottish Power also have a £63-per-year increase planned for June 1.
“The problem with this is that it impacts people who are less able, less likely, and less confident to switch to a better deal,” she said.
“At least go on a comparison website, take a look and call your company and haggle with them,” she advised.
“If you’ve got an elderly family member who’s not online, please go and help them out because you could make savings of around £300 a year which could make a huge difference to people’s lives.”
Overall, npower customers will pay the most as its 5.5% price increase will mean customers on its standard tariff will pay £1,230 per year on average from June 17.
Which? said npower customers on its standard tariff could save up to £434 by switching to the cheapest deal on the market, Utility Point's variable tariff at £797 per year, or £268 by switching to npower's own cheapest tariff.
British Gas households could save £113 if they transferred from the standard tariff to the best deal available.