The North Sea’s biggest operator has swung from a near $1bn profit to an $8m loss after the Government imposed its windfall tax and bosses cutback on investment.

Harbour Energy, which supplies about 15pc of the UK’s domestic oil and gas, said its half year results had also been hit by $16m of charges related to a review of its business triggered by the excess tax.

It hopes this will deliver €50m of savings from next year.

It comes a day after rival operator Ithaca warned it is being forced to cancel projects and reduce production because of the “severe impact” of the Government’s windfall tax. 

Ithaca Energy, which is behind the controversial Cambo oil field, has told investors it is writing $74m (£58m) off the value of assets as a “direct impact” of the Energy Profits Levy. 

Harbour chief executive Linda Z Cook said: “We remain focused on maximising the value of our UK oil and gas portfolio, advancing our organic development projects and disciplined capital allocation.”

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