More than one in eight households in England were living in draughty homes and struggling to pay their bills in 2020 – even before rising energy prices hit.

Official statistics for 2020, the most recent year for which figures are available, show there were an estimated 3.16 million English homes in fuel poverty, or 13.2% of households, down slightly from 3.18 million, or 13.4% of households, in 2019.

But campaigners warned that surging prices are now pushing millions more into fuel poverty across the UK.

In England, official statistics now consider a household to be in fuel poverty if their home has an energy efficiency rating of band D or below and their disposable income after housing and fuel costs is below the poverty line.

Energy efficiency such as insulation improved between 2019 and 2020, the figures show, with 52.1% of all low-income homes living in a property with a rating of C or above – taking them out of fuel poverty under the new measure.

In 2020, incomes grew and energy prices fell 2.6% in real terms as wholesale energy prices dropped at the start of the pandemic – although prices for those on prepayment meters rose slightly.

Director of policy and advocacy at National Energy Action (NEA), Peter Smith criticised the time lag for the data, warning that the figures are already out of date.

“It doesn’t take the October price rise into account, or any of the impacts of Covid, and we know the picture will be much worse come April when prices are expected to increase by over 50%,” he said.

Under NEA calculations that take an alternative approach to measuring the problem, which it says better reflects the impact of surging prices, some four million households across the UK were in fuel poverty by October 2021.

The NEA estimates there will be 6.5 million households in fuel poverty in the UK in April when the new price cap comes in.

And Ed Matthew, campaigns director at climate change think tank E3G, said that, since 2020, “energy bills have gone through the roof, plunging at least two million more households into fuel poverty across the UK”.

“This causes impossible choices for some on whether to heat or eat,” he said.

“The response to this energy bill crisis should be to double down on action to insulate our housing stock, the least energy-efficient in Western Europe.”

Mr Matthew urged the Government to accelerate regulation to bring private rental and social housing up to a high standard of energy efficiency, and double public investment in insulation and clean energy, prioritising low-income homes.

“That investment can boost the economy and generate jobs whilst providing the best long-term solution to high energy bills, ending the blight of fuel poverty forever,” he urged.

Simon Francis, co-ordinator of the End Fuel Poverty Coalition, said the 2020 data shows the Government has failed to tackle fuel poverty.

He said: “The impact of measures taken pre-pandemic has barely shifted the dial – and we know very little has been done since 2020 to change the picture. Indeed, the situation has become much, much worse.”

He added: “We need urgent help for households in fuel poverty now, combined with a long-term plan to improve energy efficiency of our homes and a sustainable, renewable-led energy mix.”

A Government spokesman said it is continuing to make significant progress in tackling fuel poverty, thanks to improvements made to the energy efficiency of people’s homes.

He said: “The best long-term method to keep household energy costs down is through improving the energy efficiency of our homes and buildings so we use less expensive gas, which is why we are also investing over £6.6 billion over this Parliament to these ends.

“We are also providing support worth £21 billion this financial year and next to ease short-term pressures and help working families, low-income households and the most vulnerable with energy bills.”

A recent report from the Energy and Climate Intelligence Unit said millions of homes would have saved £170 each when energy prices spike this spring if the Government had not scaled back support for measures like insulation in 2013, and if they had continued to be installed at the same rate as a decade ago.