DANA Petroleum has plunged deep into the red as it slashed the value of its North Sea business to reflect the sharp fall in the oil price.

Accounts for the Korean-owned oil and gas firm show it made a £285 million loss after tax in 2014 compared with a £105m profit in the preceding year.

The loss was stated after Dana recorded a £129m impairment charge against the value of producing assets in the UK, Norway, Netherlands and Egypt, which it said reflected the significant drop in Brent crude prices in the second half of 2014.

Korea National Oil Corporation bought Dana for £1.9bn in 2010, giving it control of a big portfolio of producing assets focused on the North Sea amassed by that company under the leadership of Tom Cross.

Dana saw income fall by around £320m in 2014, to £680m from £1 billion, partly reflecting the drop in the oil price last year. After recovering some ground in spring, in advance of the US driving season, the price of Brent crude has fallen again in recent weeks amid abundant supplies and muted demand.

Brent crude traded at around $49 per barrel yesterday compared with $115 in June last year.

In the accounts directors said Dana completed a significant restructuring in 2014 against a backdrop of operational challenges, particularly in the UK and oil price volatility.

The expected start of production from the flagship Western Isles development off Shetland has been put back to 2017 from 2015 and the project budget has increased to $2bn from $1.6bn following what Dana described as major delays in the engineering stage.

Dana’s average production fell to 41,637 barrels oil equivalent daily from 46,891 boed in 2013. It cited ongoing field decline in late life assets, extended shut downs in one area and poorer than expected reservoir performance on two UK fields.