Ed Miliband’s North Sea tax crackdown risks destroying the UK’s oil and gas industry and making Britain even more dependent on imports, a leading operator has warned.

EnQuest, which operates some of the UK’s most strategically important offshore assets, hit out at a decision to add three percentage points to the taxes imposed on oil and gas profits and strip the industry of key tax breaks.

It comes as Mr Miliband, the Energy Secretary, seeks to accelerate the shift to net zero.

A spokesman for the company said: “EnQuest is extremely disappointed by the Government’s decision to increase and extend the energy profits levy.

“Reductions in investment allowances will stifle investment in the sector and will prove to be a highly damaging move for jobs across the UK.”

The planned tax increase and loss of investment allowances were not announced in Chancellor Rachel Reeves’ recent pre-Budget speech, but instead published online late in the afternoon. Documents said that the levy was designed to tackle the “extraordinary profits of oil and gas companies” operating in UK waters.

They added: “Money raised from these measures will support our clean energy transition, increasing security and providing sustainable jobs for the future.”

Mr Miliband and Ms Reeves had repeatedly pledged that Labour would raise oil and gas taxes, but the sudden and unexpected timing sparked consternation among North Sea operators, forcing Treasury officials to organise an evening ring-round of chief executives in an attempt to reassure them.

EnQuest said the attempt had not worked.

The spokesman said: “Rather than accelerating decarbonisation, these measures will accelerate the decline of UK oil and gas production, making the country even more dependent on higher carbon imports, whilst harming a vital indigenous industry and the hundreds of thousands of jobs it supports.

“It will also have a disproportionate effect on British independent companies like EnQuest, which has invested over ￡4bn in the UK North Sea over the last decade and generates most of its revenues in the UK – as opposed to the oil majors who generate the vast majority of their profits overseas.”

Enquest operates platforms around Scotland including Magnus, the most remote in UK waters, located more than 100 miles north of Shetland.

It also operates several key pipelines that carry oil and gas from offshore platforms to onshore processing facilities such as Sullom Voe in Shetland – meaning its assets are strategically vital to the UK’s energy security.

Like many other UK oil and gas companies, it is also involved in carbon capture and storage projects where CO2 would be pumped deep into subsea rocks for permanent storage with the costs met partly by oil and gas profits.