A large seahorse found off the Dorset coast is one of the biggest ever recorded, experts have said.

The seahorse, thought to be up to 20 years old, was accidently caught by a father and son who were crabbing on Poole Bay. They photographed it before returning it to the sea.

The Seahorse Trust said it was the fourth biggest recorded since records began in 1994.

The trust's Neil Garrick-Maidment said it was a "brilliant find".