The most powerful Conservative outside London has warned he will not hesitate to stand up to the party should it attempt to retreat from its pledge to tackle the climate crisis. There are already serious concerns that Rishi Sunak and his advisers are using green policies as a political dividing line with Labour in an attempt to revive the party’s fortunes. The prime minister recently backed “maxing out” oil and gas reserves, while cabinet minister Michael Gove said net zero should not become a “religious crusade”. Tory MPs have also demanded a delay to the ban on petrol car sales by 2030. However, in a significant intervention, Andy Street, the mayor of the West Midlands, said the party needed to “hold our nerve” in its commitment to tackling what he described as the “defining issue of our time”. In an interview with the Observer, Street said that Britain would be put at a competitive disadvantage should it back away from reducing carbon emissions. He said supporting the green agenda would help the party with voters – and that others who shared his view needed to be prepared to speak out. “If you want to take the green agenda as an example, what was the most successful area of investment for [the West Midlands]? Green manufacturing,” he said. “There’s opportunity in that. There’s also a social responsibility to step up. So people like me have to stand up and be counted on it. “The electoral point is equally, in my mind, extremely clear. This is a defining moral issue of our time. Are we going to be the party that guides this country through addressing climate change? It’s the right thing to do. The thinking voter will see that. The problem is, it’s been defined as a choice, but there isn’t a choice to stand still. Actually, the win-win of going with the change has not been sufficiently well described. So that’s what we’ve got to step up to do.” Sunak’s apparent pivot away from green policies came in the wake of a surprise by-election result in Uxbridge last month, in which the Tories scraped a 495-vote win. Its campaign was centred on opposing the ultra-low emission zone (Ulez) extension imposed by Labour mayor Sadiq Khan. Street said the result should not be misinterpreted. “Uxbridge was about Ulez,” he said. “It was not about Britain’s commitment around net zero. I find it a source of pride actually, that the previous Conservative government put us as world leaders in this. Theresa May enshrined it, Boris Johnson led us very well in Cop26. People like me have to stand up and make sure we don’t lose our nerve on it.” He said the electrification of cars was now taking off: “We’ve got a choice as to whether we are going to be part of leading that, or whether we’re going to deny the change and lose the opportunity to lead. And there are tens of thousands of people, particularly across Coventry and Warwickshire, already employed in that sector, drawing inward investment in its millions of pounds in that sector. This change is happening.” Street, now seen as a leader of the levelling up agenda since the departure of Johnson, had been critical of what he described as the government’s “begging bowl culture” of handing out funding to local leaders. However, he said new powers that gave him far more control over a single pot of money had been a major breakthrough. He recently made training courses free for those earning less than £30,000 a year. He said he next wanted the region to be able to raise taxes and keep more of the tax paid in the West Midlands. “We’ve got to demonstrate what we’re going to do with these new powers,” he said. “Then there can be a lot more. We’re still asking to spend government money. Where I want to get to is raising the money here, and we will hold it here. That doesn’t have to be new taxes. That can be taxes that are already levied in the West Midlands held here.” Street, a major advocate of the HS2 train line, also expressed exasperation at the opposition to the project within his party and said the scheme had been mis-sold. “The bloody thing’s already being built,” he said. “It’s happening in front of our very eyes. “It’s been sold as reducing journey times between principal cities, but it’s actually about providing a public transport system for the spine of the country that’s going to last 100 years,” he said. “If you divide the annual investment by 100 years, it seems pretty reasonable. The Victorians did that and we’re still running on what’s essentially the same Victorian railway. And that is going to drive economic redevelopment of those key cities. The country as a whole needs that because some of the overheating in the south-east.”