Almost half of people referred to foodbanks are at risk of going cold as well as hungry this winter, a new study reveals.
People on pre-payment meters are particularly at risk of having to choose between heating or eating, said the Trussell Trust.
A survey of its more than 400 foodbanks showed that almost half of people given emergency food supplies might not be able to afford to pay for heating or hot water.
Only one in seven foodbanks operate in areas where a local council-led fuel poverty scheme was running, said the Trust.
Chief executive David McAuley said: "A crisis in winter for someone on a pre-payment meter who can't afford the bare essentials isn't just shocking, it's dangerous.
"We've met a grandma who went without food and heating as she waited six weeks for a delayed pay cheque, and a family using candles over the Christmas period because they can't afford to put the lights on.
"Without the superb support offered by foodbanks and schemes like the Fuel Bank, people would be going cold, hungry, and falling seriously ill. We're pleased at the recent price cap, which will bring down bills for pre-pay customers, but more can be done to ensure people aren't going cold and hungry in the UK this winter."
A Government spokesman said: "The Government is committed to tackling fuel poverty.
"The Warm Home Discount will ensure that more than 2 million households will receive £140 off their energy bills this winter. This is in addition to Winter Fuel Payments, Cold Weather Payments, and the range of other social security benefits on which - for people of working age alone - more than £90 billion a year is spent.
"The best long-term solution to fuel poverty is to improve the energy efficiency of households - and we are reforming the requirement on energy companies to install efficiency measures in homes across Great Britain, which will insulate 1 million homes by 2020."