Millions face a £67-a-month jump in energy bills from today.
It comes after the Tories scrapped the support package which gave households an extra £400 to cover soaring costs.
The scheme has been replaced with more targeted aid but critics say many will miss out.
Campaigners have dubbed today April Fuel’s Day and plan to lobby MPs across the country.
The Warm This Winter campaign says three in 10 people are already in debt to energy companies.
Under pressure, the Government extended its Energy Price Guarantee, pegging a typical annual bill at £2,500. But that is still well above last year’s £1,971 and does not take account of the withdrawal of the £400 universal help.
Simon Francis of the End Fuel Poverty Coalition said: “People are being taken for fools. The Government says it is providing support but bills are going up.”
TUC General Secretary Paul Nowak said: “Ministers have been far too fast to withdraw the scheme.”
Meanwhile leisure trade body UKHospitality slammed “profiteering” energy suppliers as its members brace for a potentially crippling surge in bills.
