The Government’s infrastructure tsar has warned Philip Hammond he must fully commit to a major programme of upgrades to the UK’s transport, energy and technology networks.

National Infrastructure Commission (NIC) chairman Sir John Armitt has written to the Chancellor demanding action to meet the challenges facing the UK and help tackle climate change.

NIC sources told the Press Association Sir John is “holding the Treasury’s feet to the fire” ahead of the Government’s official response to the body’s recommendations for a major programme of improvements across the country by the middle of the century.

Sir John warned against a strategy built on “vague promises” that only paid “lip service” to his body’s recommendations.

In a letter to the Chancellor, Sir John set out four key tests by which his commission will judge the credibility of the Government’s National Infrastructure Strategy, which is expected to be announced at the autumn spending review.

Sir John said: “Building the right infrastructure for the mid-21st century will help Britain shape a new national and global identity. One built on optimism and confidence.

“The Government must not deliver a weak strategy that pays only lip service to our recommendations.

“We don’t want to hear vague promises and a restatement of existing commitments.”

The four tests set out by Sir John in his letter to Mr Hammond are:

– A long-term perspective, looking beyond the immediate spending review period and instead setting out plans up to 2050.

– Clear goals with specific plans to achieve them and firm deadlines.

– A firm funding commitment to invest 1.2% of GDP a year on infrastructure.

– A genuine commitment to change, meeting NIC recommendations to devolving funding for urban transport to cities and a national standard for flood resilience.

Sir John said the four tests are the “minimum requirement” for the Chancellor.

In its assessment published in 2018, the NIC’s proposals included nationwide full fibre broadband by 2033, half of the UK’s power to come from renewables by 2030, and £43 billion of transport funding for regional cities.

The infrastructure assessment also called on ministers to prepare for all new vehicle sales to be electric by 2030.

In his letter to Mr Hammond, Sir John welcomed the commitments already made by the Government in its plans for expanding fibre broadband accessibility, improving the resilience of the water supply, and tougher standards on waste and recycling.

Sir John said: “The commission was established to encourage a radical change in the way the UK plans and funds its infrastructure for the long-term. These four tests represent our minimum requirements ahead of this autumn’s spending review for determining the effectiveness of the Government’s response.

“We’ve seen positive steps from Government in adopting our recommendations on reducing water leakage and tackling waste.

“But those were the easy wins. Real change is required if we are to boost our economic prosperity and quality of life up to 2050.

“That requires the Government’s National Infrastructure Strategy to be bold and transformative and commit to major changes like devolving funding for cities transport.

“We’ve put forward a costed plan for how we do that, backed up by a wealth of new evidence in support.

“We now need the Government to step up to the plate and share our ambition to create a bold future for the infrastructure that people across the country will use every day of their lives.”

A Treasury spokeswoman defended major infrastructure plans.

She said: “In this parliament, public investment will reach its highest sustained level for 40 years, helping fund major improvements to our infrastructure.

“This includes the biggest rail investment since Victorian times, and the largest ever strategic roads programme.

“The Government will respond in full to the NIC’s assessment through a National Infrastructure Strategy which will be published later this year.”

David Hughes is Press Association Political Editor.