A GARDENER dug up a dinosaur bone in the back garden of his North East home.

The man, who wishes to remain anonymous, was digging when he unearthed the hefty bone in Sunderland.

And when he took it to the citys Museum and Winter Gardens, it was identified as a bone from the tail of an Iguanodon dinosaur, which grew up to 10 metres long.

Sylvia Humphrey, keeper of geology at Tyne and Wear Archives and Museums, was on hand when the bone was brought in.

She said: When the man unwrapped it, my first thoughts were that it was from a whale or a dinosaur.

But then it didnt look like the right shape for a whale bone and you dont find dinosaur bones in Sunderland.

Sylvia circulated information to experts, and specialists at the Natural History Museum in London verified the find.

Dr Angela Milner from the paleontology department at the Natural History Museum said: The bone is the solid part of vertebra from the tail of an Iguanodon-like dinosaur. Sylvia said: How the bone from what is a quite a big beastie came to be in Sunderland is a bit of a mystery.

Its really quite a puzzle as dinosaur bones are younger than the rocks of this area which are 250 million years old.

The rocks of this region are far too old for it to have lain here.

Iguanodon walked the Earth 130 to 115 million years ago.

One theory is that the bone could have been carried by a glacier to the spot, or it could have come from the collection of a 19th Century amateur naturalist, which was a booming interest at the time.

Well-to-do individuals often developed a Cabinet of Curiosities in their homes to entertain guests.

Another clue is the North East 19th Century naturalist William Hutton, whose collection of Iguanodon teeth and bones is in the Great North Museum in Newcastle.

He acquired the specimens from a 19th Century doctor called Gideon Mantell, who found them in the Wealden rock formation in Kent, which has historically yielded many dinosaur fossils, mostly that of Iguanodon-like creatures.

The dinosaur bone is now on display in Sunderland Museum and Winter Gardens.

Jo Cunningham, manager of Sunderland Museums, said: We are very grateful to our museum visitor for bringing this amazing find in to us.

It will always remain a mystery as to how it found its way there.

Iguanodon was a vegetarian, which was distinguished by a thumb-like spike.