Hundreds of thousands of some of the most vulnerable households are not protected by the energy price cap, social housing providers warn.

For people living in buildings where their energy is supplied through a communal heating system, their energy costs are uncapped. The amount they will pay will depend on the commercial contract their housing provider negotiates with the energy company.

According to the National Housing Federation (NHF), recent contracts are as much as 500% more expensive than the previous year, with bills in low usage homes projected to rise by as much as £68 a week. This increase alone is £1,130 per year over October’s energy price cap.

The NHF warned that over half of households on communal heat networks (227,848) are living in social housing and on low incomes. Nearly three-quarters (72%) are older people over the age of 55.

The housing body urged the Government to act urgently to ensure people on heat networks receive the same protection as customers on domestic gas supplies.

Kate Henderson, chief executive of the NHF, said: ‘It is unjust that hundreds of thousands of people, through no fault of their own, are exposed to uncapped heating bills just because of the way they pay for their energy. Worst still, the majority of those affected are vulnerable people on the lowest incomes in this country, who will already be struggling to pay for food and essentials.

‘The Government has a duty to act urgently and fairly to protect these people in the same way as the rest of the country. With the price cap coming into force in October it is essential that the government acts now and negotiates with energy companies to ensure every resident is protected from rising energy bills.’