A blue whale has been spotted about 250 miles off the south-west coast of Cornwall.
The "incredibly rare sighting" was recorded by scientists studying deep sea environments from the Royal Research Ship James Cook.
Professor Russell Wynn, from the National Oceanography Centre in Southampton, photographed the huge mammal - twice as long as a double-decker bus - on August 24.
The creature was swimming over a deep sea canyon on the northern edge of the Bay of Biscay.
Prof Wynn said: "I was undertaking our daily marine mammal survey and enjoying watching up to seven fin whales around the ship, when the blue whale suddenly surfaced about a kilometre away. I had just enough time to secure some conclusive photos before the visibility decreased and the whale disappeared into the gloom."
The last sighting of a blue whale so close to the UK occurred in September 2008 when one of the animals was photographed off south-west Ireland.
Blue whales were hunted to near-extinction in the north-east Atlantic in the early 20th century but experts believe the population is slowly starting to recover and moving into new areas.
Dr Veerle Huvenne, also from the NOC and the expedition's chief scientist, said: "There was huge excitement on board as many people got a glimpse of their first blue whale.
"The Biscay margin is already recognised as a hotspot for whales, dolphins and seabirds - our new data further underline the importance of this area for iconic marine life."