The diver was airlifted to a decompression chamber

She was understood to have suffered the bends - decompression sickness - off the fishing village of St Abbs, north of Eyemouth.

The woman, from Suffolk, was being treated in a hyperbaric chamber.

An area of the North Sea, off St Abbs, is popular with sub-aqua enthusiasts because of the clarity of the water.

A helicopter from the RAF base at Boulmer in Northumberland carried out the mission, with the crew limiting its altitude to avoid worsening the 34-year-old diver's condition.