Three offshore workers were airlifted to hospital last night after being injured when their vessel was hit by a freak wave in the North Sea.

The incident comes a year after a fatality on the same vessel. There were 70 people on board the Bleo Holm, a floating production and storage offloading vessel, which was working for Talisman Energy (UK) Ltd, 72 miles north east of Aberdeen when the incident occurred.

All 70 were accounted for, but four were injured when items on the deck of the vessel broke free as it was hit by severe gale force winds in excess of 40 knots and waves almost 30ft high.

One of the men suffered minor injuries and remained on board but, after consulting with a doctor in Aberdeen, it was decided his three colleagues should be flown to Aberdeen Royal Infirmary.

The BP Jigsaw rescue helicopter, Bond Rescue 1, was in Aberdeen and flew to the scene. Conditions prevented it from landing on the 250-metre-long vessel, so the casualties were winched aboard.

Two were stretchered into an ambulance at the hospital helipad and one was able to walk. No reports on their conditions were available.

On January 6 last year Matthew Grey, 59, of Darlington, suffered fatal injuries while fitting pipes in one of the cargo tanks on the Bleo Holm. His workmate, Norman Jackson, 58, of North Shields, escaped with an arm injury.

Talisman UK's vice-president Nick Walker later admitted that some of its safety systems were not up to standard.

He said: "Our investigation has shown that some of our systems were not sufficiently robust, principally in the establishment and maintenance of safe areas during lifting, communication and lifting and rigging procedures."