The two bodies said: “In our responses to the EAC’s consultation last year, we highlighted how two thirds of oil heated properties (765,000 homes) currently fall into the lowest energy efficiency bands of E-G, making them far more difficult and expensive to improve.

“Instead of representing an ‘easy, early win’ for decarbonisation, off-grid properties present one of the most costly and complex challenges. This means the majority of households will need considerable financial support to achieve the levels of improvement required – not just the fuel poor.

“Consumer choice and fairness must lie at the heart of future decarbonisation policy for government to get back on track. Households, especially those off-grid, must have access to a range of simple to implement, affordable options that work for a variety of property types and budgets.

“Failure to embrace a mix of solutions going forward – which should include renewable liquid fuels as a near drop in replacement for oil heated homes – will continue to threaten progress.”