A giant fish washed up on a Pembrokeshire beach yesterday (Wednesday)is thought to be the first of its species ever seen in British waters.

Weighing in at around 450 pounds and over seven feet long, the magnificent Blue Marlin was found in the surf on Saundersfoot's Glen Beach on Wednesday by commercial fisherman Gavin Davies.

"I saw something in the water the previous evening, but it wasn't until I was walking the dog at 5.30am that I realised it was a marlin," said Gavin. "It was an amazing specimen."

He and fellow fishermen Neil Lewis, Mel Matthews, Neil Thomas and Ruru Norbury pulled the marlin onto the beach with a Land Rover, before lifting it on the vehicle and contacting South Wales Sea Fisheries officer Mark Hamblin to verify their fishy find.

"I was gobsmacked," admitted Mark. "I would have loved to have caught that with a rod and line!"

The marlin, usually found offshore in deep blue tropical or temperate waters, is known to migrate towards the Atlantic, but apparently never as far afield as the UK.

"We are wondering if it could have been attacked by dolphins out at sea, and just drifted in," said Gavin, who fishes for Neil Thomas on board the Evan George.

"We're currently seeing dolphins by the hundred when we are out in Carmarthen Bay, and they are known to be extremely aggressive to other fish."

The fishermen have now disposed of the marlin to a watery grave well out at sea - with just a passing thought at the money they could have made if he had actually been their catch.

"He would have been straight up to Billingsgate Market and we would have earned around £4,000!" revealed Gavin.