Victim: Some of the most vulnerable customers have seen their energy bills rise by 75 per cent
French-owned EDF has announced a 22 per cent rise in gas bills and 17 per cent on electricity for its 5.5million UK users.
At the same time, it has secretly raised gas prices for some of its most vulnerable customers by as much as 75 per cent.
The increases are in stark contrast to the situation in France.
EDF has been told by the government there to cap its increases on electricity to just 2 per cent and gas to 5 per cent.
There are fears the company, which is part-owned by the French government, is looking to protect its profits by imposing punishing increases on UK families.
The price cap in France will not stop EDF imposing big rises in the cost of electricity it sells to Britain via a cable under the Channel.
The increases were strongly criticised yesterday by Ed Mayo, chief of the National Consumer Council.
'Closed and protectionist European energy markets end up picking the pockets of consumers in this country,' he said.
He suggested Britain should consider introducing French-style price caps. 'If the French are capping prices, that is something we should be looking at. We should learn from the French,' he said.
'My concerns are for people on fixed income, such as pensioners, who will be switching off their electricity and heating this winter. That will lead to more illness and disease.'
Mr Mayo said foreign owned power companies - such as EDF, RWE Npower and E.on of Germany, and Iberdrola of Spain, which owns Scottish Power - must show they are not raising prices in the UK to subsidise customers in other countries. He was speaking at a press conference to announce the name of a new 'super-watchdog', Consumer Focus, which will replace the National Consumer Council, Energywatch and Postwatch.
EDF, like the other 'big six' power suppliers, has a series of tariffs linked to the amount of gas that customers use.
It has increased the charge for 132,000 low users by up to 75 per cent - taking the charges up from 3.984p per kilowatt hour to 7p. A low-user customer who perhaps only has gas for a cooker will see the annual bill rise from £106.77 a year to £187.60.
EDF customer Philip Williams, 69, who lives alone in Walton-on-Thames in Surrey, said: 'I couldn't believe it when I got the bill and found the price had gone up by 75 per cent, not 22 per cent as we were told. I've had no notice that it would go up this much.
'During the winter months my bills will go through the roof.'
Consumer group Energywatch said: 'The message this sends out is that people who try to be careful and cut down on their use of gas end up getting penalised with bigger increases in bills than everyone else.
'All the evidence is that energy companies are disregarding the needs of their most vulnerable customers.'
LibDem energy spokesman Steve Webb suggested firms such as EDF may try to boost profits in Britain to counter price caps in their home countries.
'EDF will have to make up the shortfall somehow,' he said. 'They may have to look to customers in Britain.'
The 'big six' power suppliers also charge more than 3.5million customers who have prepayment meters around £150 a year more for their heat and light compared with those who pay via direct debit.
These firms offer social tariffs which are supposed to cut the bills of the estimated 4.5million households which are in fuel poverty.
However, the deals are wrapped in small print with the result that only a tiny fraction of eligible households are signed up.
A spokesman for EDF denied UK customers will subsidise those in France. He said both are standalone profitable businesses.
He added: 'EDF Energy has always taken its responsibility to vulnerable customers very seriously and has gone far beyond regulatory obligations to support customers struggling to pay energy bills and to keep warm.'