LONDON The British government plans to increase a windfall tax on North Sea oil and gas (O&G) producers would lead to a nearly 12 billion pound (US$16 billion) drop in revenue to the state and accelerate a decline in output, an industry group said on Monday.

The Labour government, elected in July, has said that the changes will help achieve a ramp-up in renewable power and shift from O&G, to reduce carbon emissions and help curb global warming.

Industry group Offshore Energies UK (OEUK) forecasts that the changes would reduce tax revenue by 12 billion pounds between 2025 and 2029, compared to the current tax regime.

Capital investment in the sector over the period is expected to fall to 2.3 billion pounds, from around 14 billion pounds, OEUK said.

The proposed tax changes "will trigger an accelerated decline of domestic (O&G) production, and a corresponding reduction in taxes paid, jobs supported, and wider economic value generated," OEUK chief executive officer David Whitehouse said in a statement.

North Sea focused NEO Energy said the fiscal and regulatory uncertainty would slow investments across its portfolio.

NEO owns half of the Buchan Horst development project in the UK North Sea, with Serica Energy and Jersey Oil & Gas owning 30% and 20%, respectively.

Production in the mature North Sea basin has declined from a peak of 4.4 million barrels of oil equivalent per day (boed) at the start of the millennium to around 1.3 million boed today.

The North Sea Transition Authority (NSTA) regulator has forecast that it will decline to less than 200,000 boed by 2050.

Shortly after its election, Britain's Labour government said it would increase the Energy Profits Levy (EPL) to 38%, from 35%, starting Nov 1, bringing the headline rate of tax on O&G activities to 78%, among the highest in the world. Its duration was also extended by a year to March 2030.

The changes will also include scrapping the levy's 29% investment allowance, which lets companies offset tax from capital that is re-invested.

A Treasury spokesperson said: "We are committed to maintaining a constructive dialogue with the oil and gas sector, to finalise changes to strengthen the windfall tax, ensuring a phased and responsible transition for the North Sea".

  - Reuters