UK North Sea operators are up in arms over a looming increase in a windfall tax on oil and gas profits that was introduced only four months ago, with the largest industry trade group claiming the rise would force companies to pull investments in new projects and lead to an exodus that would undermine the government’s calls for greater energy security.

UK Chancellor Jeremy Hunt is preparing to introduce a package of tax increases later this week and looks set to increase from 25% to 35% a surcharge on oil and gas profits put in place earlier this year.