A surfer has said he spotted one of the world's most dangerous sharks in the sea off west Cornwall.
Luke Goodman left the water quickly after seeing the fish
Luke Goodman, 25, from Penzance, said a bull shark at least 6ft (1.8m) long swam under his surfboard while he was in the water near Sennen Cove.
Bull sharks are from the same family as the reef shark. They can be up to 11.5ft (3.5m) in length and are known for their attacks against bathers.
But experts have said they have never been seen in European waters before.
Basking sharks are a common sight around Cornish waters in the summer, but they are plankton-eating fish, not human predators.
Luke Goodman said: "It wasn't a basking shark because it was too small. It didn't have a long, dark dorsal fin.
"It was stocky, box-shaped and had a very rounded nose which rules out the makos too.
"It also had a slow but powerful swim, so it wasn't a seal or dolphin."
A few weeks ago, fishermen off the north Cornwall coast reported seeing another type of a very fast swimming shark - the mako.
But experts discounted the possibility of makos in South West waters and said there was very little chance of seeing a bull shark.
Rolf Williams, of the National Marine Aquarium, said: "Looking at our understanding of the natural history bull shark, it is extremely unlikely that one was in our waters. Equally, it's extremely difficult to identify one with certainty from the surface of the water.
"It's more likely to have been something like a beagle shark, which grows to 9ft (3m)."
Luke Goodman, however, said he had no doubt that he made the right choice to get quickly out of the water after seeing the fish.
He said: "If it wanted to, it could have taken a good old chunk out of me."