Boris Johnson is being urged to fulfil his 2019 election manifesto pledge to invest £9.2bn in a massive insulation programme to make homes, schools and hospitals more energy efficient.

Few details have yet emerged about the policy, but a major national effort to address buildings’ inefficiencies is regarded as a major means of reducing emissions and enabling the UK to hit net zero by 2050.

The House of Commons’ environmental audit committee has now announced an inquiry into home insulation, and it has emerged that Downing Street chief adviser Dominic Cummings reportedly sought to water-down the pledge, and instead focus on building more houses.

Mr Cummings privately argued the cash should be spent on building homes, with insulation a priority for later on, according to the Financial Times.

But the environmental audit committee has warned that without the insulation programme, the UK will miss its 2050 net zero target.

In a letter to the chancellor Rishi Sunak, the chair of the committee, Philip Dunne, along with Darren Jones, the chair of the Business, Energy and Industrial Strategy Committee, said economic recovery from the impact of the coronavirus pandemic, was a “a major opportunity to accelerate investment on climate adaptation”, which could “spur innovation, create jobs and bring substantial economic benefits”.

The MPs said: “Droughts, floods and other extreme climate-related events have increased both around the world and in the UK. Climate scientists are telling us we only have a short window of opportunity to keep global temperature rises to a manageable level.”

“If recovery packages are not aligned with net zero, then the world’s nations could end up investing in carbon-intensive energy, transport and industrial infrastructure projects that lock us into high carbon pathways for many years to come. This would be a historic mistake,” the letter adds.

They make an economic case for putting environmental concern at the centre of the government’s coronavirus recovery.

“Investing in shovel ready projects in areas such as home energy efficiency will create jobs, grow supply chains and deliver energy and cost savings in the longer term. There is evidence that such an approach would be supported by the public: 79 per cent of the members of Climate Assembly UK ‘strongly agree’ or ‘agree’ that the government’s economic recovery efforts should be designed to help achieve net-zero,” they write.

The letter to the chancellor comes as the Energy Efficiency Infrastructure Group – a collection of charities and organisations aiming to improve the efficiency of the UK’s housing stock, has produced new evidence for why a large-scale insulation programme could make such a difference.

A report by the group suggests jobs in home insulation can be created for around £59,000 – far less than a road maintenance job, which is estimated by the government to be more than £250,000, and therefore represents far better value to taxpayers.

The analysis estimates around 40,000 jobs in insulation could be created by the government over the next two years, and 150,000 in the next 10.

The author of the research, Pedro Guertler, told BBC News: “Really this is a no-brainer. It’s fantastically good value for money – it should have been done years ago. We can hit so many government objectives at the same time.

“It’s obvious that insulating homes provides very good value – far, far better value for the taxpayer than building roads, for instance.”

The government’s manifesto pledged £28bn for roads – three times what it said it would spend on insulation. Around 4,000 miles of new roads are planned, while this week Green Alliance, a think tank, warned: “Even with the current 2035 phase-out date for petrol and diesel cars, we can’t shift to electric vehicles fast enough to meet our carbon budgets. We can’t afford further road expansion.”

Last month Mr Johnson said the government’s commitment to net zero by 2050 “remains undiminished” by the impacts of the coronavirus pandemic.

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