A giant devil crab which is more than three times heavier and almost twice as big as normal has been donated to Newquay’s Blue Reef Aquarium after being caught by a local fisherman.

The velvet swimming crab – which is also known as a devil or witch crab – was caught by Mylor fisherman Ned Bailey in a crab pot about a quarter of a mile south east of St Anthony Lighthouse in Falmouth Bay.

Normal specimens usually weigh around 90 grams with a shell that measures six centimetres across. However this crab tips the scales at a whopping 268 grams and is more than ten centimetres across.

Blue Reef curator Matt Slater said: “We’re still not sure that he’s the biggest ever caught in the UK but he’s certainly the largest anyone here has ever seen and he’s significantly heavier and longer than anything we can find in our reference books.

“A crustacean’s size and weight are all due to a number of different factors including diet, environment and even water temperature. It may also be that this is a particularly old individual but even taking all those factors into account he really is a bit of a monster – and very feisty with it!”

Although they rarely exceed ten centimetres in length they will try and attack even the largest intruder – including humans - waving their claws violently from side to side.

Velvet swimming crabs get their name from the fact that their shells are covered with dense, velvety hair and they are also able to use their paddle-like hind legs to swim away from attackers like cuttlefish.

They are found from northern Norway to the Mediterranean and the Black Sea living on rocky shores below the low tide mark and are often found lying in wait under stones in rockpools.