A shark has reportedly spotted in Cornwall by fisherman. Harbour officials have confirmed two people on separate boats had reported seeing an oceanic white tip shark about a mile (1.6km) off the beaches of St Ives.

A spokesman for the office, however, has refused to confirm that the creatures spotted were oceanic white tips.

He said that people should not “blow the reports out of all proportion”, but  that ”people are starting to panic”.

Ian Bullus, 60, spotted the beast’s distinctive mottled dorsal fin zig-zagging towards his 16ft mackerel boat Dreamcatcher.

He said: “As I was looking over the side of the boat it just slammed into it. Its head came out of the water by about a foot.

“It slammed the boat with its body and tail. It was very aggressive.”

Minutes later two fishermen on a second boat were circled by the 7ft shark.

One said: “The water was crystal clear and we had a perfect view. It was scary.”

St Ives Mayor Ron Tulley said: “No one has ever been injured by a shark in St Ives. I don’t want it to put people off coming here.”

Study group the Shark Trust confirmed the fishermen’s description matched that of an oceanic whitetip.

Whitetips, described by undersea legend Jacques Cousteau as the deadliest shark, are previously unknown in UK waters.

But experts say global warming has heated up the seas off Devon and Cornwall – making them more attractive to species such as the whitetip shark

The killer shark is usually found far further south in deeper waters away from the coast, with Portugal being the usual northern-most reach of its habitat.

It has been known to attack humans.

Basking sharks are regular visitors to the county’s shores, appearing each summer to feed on plankton.

Other species have been found washed up on county’s beaches, including a 12ft (3.8m) thresher shark, which was found in Hayle in 2009.