The dino makes "wicked" movements

"The larger movements are so much more fluid and the smaller, cell movements are that much more subtle," said Audrey O'Connell, head of international business development at the museum.

The T. rex thrashes its tail and curls its lips before sweeping its jaws down to head height as if to bite the nearest human. Its roars echo around the museum.

The top London visitor attraction is developing the technology with Japanese animatronics company Kokoro. The two organisations hope to sell similar beasts to science and dinosaur galleries around the world. This particular T. rex model can be purchased for �220,000.

Eating program

When London visitors get to see the robot dino from 17 February, it will be in a pit eating its prey. "We can vary its movements," said Dr Milner, "and when it goes in the dinosaur pit it will be programmed with an eating cycle and will make noises to match."

School children visiting the museum on Tuesday were given a sneak preview of the beast. They even got up close to stroke the carnivore as it grunted and shook its head. "It's really, really cool," said the pupils from Christ Church CE School in Battersea, London. "It's got wicked movements."

The museum had hoped to waft T. rex breath (the smell of rotting flesh) around the gallery. "Unfortunately, we found the smell to be so terrible it would have put people off," said Audrey O'Connell. "So, instead, we've gone for the smell of the swamp in which T. rex would have stood."

The smell, available in small bottles for those who want to take it away with them, is described as acrid and slightly smokey. This correspondent thought it a cross between mothballs, honey and a whisky that had gone past its best.

The smell has been called Maastrichtian Miasma. Maastrichtian from the Cretaceous chalk layers uncovered on the outskirts of the Dutch town of Maastricht, and Miasma meaning noxious emanation.