(Bloomberg) — US President-elect Donald Trump hit out at the UK’s windfall tax on oil and gas producers in a social media post Friday, adding to criticisms from his incoming administration of Prime Minister Keir Starmer’s agenda.

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“The UK is making a very big mistake. Open Up the North Sea. Get rid of Windmills!” Trump wrote on Truth Social early Friday. The post linked to a November report that US oil firm Apache plans to exit the North Sea after the UK’s Energy Profits Levy rendered operations in the country “uneconomic.”

In its first budget, Starmer’s government confirmed a three-percentage-point increase in the windfall tax to 38%, bringing the headline rate for UK oil and gas producers to 78%, and prolonged the levy until March 2030. The tax had been introduced in May 2022 by the former Conservative government in the aftermath of of Russia’s invasion of Ukraine, when soaring oil and gas prices delivered exceptional profit to producers.

The Labour Party had also promised during last summer’s election campaign to stop issuing North Sea licenses for new oil and gas exploration. The pledge contrasts with Trump’s plans to encourage more domestic oil and gas development in the US.

Trump’s comments follow on the barrage of attacks launched by Elon Musk against Starmer in recent days. The world’s richest man, who backed Trump during last year’s vote and has since been named to co-head a new Department of Government Efficiency, has questioned Starmer’s record as Britain’s Director of Public Prosecutions before entering politics, called for new elections to be held in the UK, and criticized proposals to regulate social media platforms including Musk’s X.

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