UK opposition leader Keir Starmer will commit his Labour Party to boost domestic steel-making as he battles to get trade unions to get behind economic plans that are central to his pitch to voters.

“Steel is integral to a modern economy,” Starmer will say on a visit to British Steel in eastern England on Thursday, according to his office. “My Labour government will back it, secure it, and grow it, creating high-paying, productive jobs in communities all over the country, for generations.”

The commitment follows criticism from unions — who are key financial backers of the party — over Labour’s plan to ban all new licenses for oil and gas drilling in the North Sea. With Labour enjoying a double-digit lead over Rishi Sunak’s Conservatives in national polls, Starmer is eager to underline his reforming credentials as a premier-in-waiting while still appealing to his party’s base.

Read More: Starmer Seeks to Reassure UK Unions His Labour Is on Their Side

Steel will be a key part of Labour’s plan to use domestic renewable energy to boost the economy, Starmer will say. The “green prosperity” strategy will fuel demand for millions of tonnes of UK steel, Starmer’s office said.

Starmer has compared his energy plans with the US President Joe Biden’s Inflation Reduction Act, a $369 billion package of tax cuts and subsidies for green industries. That “ground-breaking legislation has created more jobs in seven months than the UK has in seven years,” the Labour leader will say.