Prosafe’s Safe Boreas accommodation vessel has been given a one-month extension to its time at Equinor’s Mariner field.

The firm said the extension is worth £4.1million and means the vessel can accommodate workers for the early production phase at Mariner through to October.

Mariner, which lies 95 miles east of Shetland, came on stream yesterday and is expected to produce 300million barrels of oil over 30 years.

It is the fourth of six one-month options Equinor has exercised to extend Safe Boreas’ time at the field.