Recovery operations are continuing after a North Sea drilling platform lost anchors during Storm Babet.

Stena Drilling said four of the eight anchors detached themselves from semi-sub drilling unit Stena Spey due to the "severe weather conditions".

The incident is reported to have started at around 6.45am on Saturday morning on the rig, which is situated around 146 miles (235 km) east of Aberdeen.

HM Coastguard confirmed it had sent two of its helicopters to assist the platform.

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Non-essential personnel were transferred from the drilling unit to neighbouring platforms and to Sumburgh on the Shetland Islands on Saturday.

Stena Drilling has since confirmed that all 45 non-essential personnel were safely returned to Aberdeen on Sunday.

The personnel who remain onboard the Stena Spey are “safe and well”, the company said.

A tow line was successfully attached from a tow vessel to the drilling unit on Sunday, with the unit remaining in a “secure position”.

Two anchor handling vessels arrived at the site on Tuesday to begin anchor recovery operations, Stena Drilling added.

A Stena Drilling spokesperson said: “Stena Drilling’s priorities continue to be the safety of all personnel and the company is working closely with partner organisations and relevant authorities including the Health and Safety Executive (HSE) to ensure the safety of all involved. 

“Stena Drilling wishes to thank the Coast Guard Services, the Authorities and the crew who reacted in so timely and in a professional manner to this weather- related emergency. Further information will be released as it becomes available.”