The world's biggest egg is set send to Chelsea antique enthusiasts into shell-shock today as it goes on sale.

The eggtra-ordinary orb was hatched in the early 17th century. It was laid by the now-extinct great elephant bird of Madagascar, a flightless beast which could weigh up to half a ton and measured 10ft tall.

Hundreds of years later, it has been painstakingly put back together from shell shards and will be put on sale at the Chelsea Antiques Fair, held in the Old Town Hall this week. It is one of world's largest eggs and has a circumference of more than a metre.

Antiques dealer John Shepherd scrambled to lay his hands on an elephant egg for more than 20 years before finding this example.

He said: "I saw two in Paris a decade ago before getting this one. My grandchildren think it's wonderful."

For a year the egg sat in a bowl on Mr Shepherd's dresser, but now he feels like it's time to pass on the egg to someone willing to shell out around £5,000.

"I'd like it to go somewhere it was appreciated," he said.

The fair is on until March 29.