A police investigation has been launched after an extensive search and rescue operation failed to find a missing fisherman off the Westcountry coast.

The man fell overboard from a Belgian fishing vessel off North Devon, sparking a major search by lifeboat crews, fishing vessels and a helicopter.

Lifeboats from Padstow and Appledore searched waters 12 miles off Hartland Point on Saturday evening along with a Sea King from RMB Chivenor.

Crews were stood down after around three hours when conditions and visibility worsened.

A spokesman for Dyfed-Powys Police, who joined Falmouth and Swansea coastguards in coordinating the hunt, said the Belgian boat had now returned to port at Milford Haven, in south Wales.

"Officers here are investigating the incident and inquiries are currently ongoing," he added. Crew members on the trawler reported a man overboard at around 6pm on Saturday.

The volunteer crews of the Tamar-class all-weather lifeboats from Appledore and Padstow were launched after the alert was raised locally at 6.20pm.

The Mollie Hunt quickly joined crew aboard the Spirit of Padstow and began to follow co-ordinated search patterns as they attempted to trace the missing crew member.

Chivenor's 22 Squadron search and rescue helicopter crew scanned the seas in freezing, rainy conditions.

Captain John Rowe described the conditions as "very poor with heavy rain".

Tamsin Thomas from the RNLI said: "When the lifeboats went out it was quite peaceful and quiet but the weather came up during the operation."

The missing man has not been named by police.

Related:

Trawlerman missing after falling into sea off Hartland Point