Visitors have to queue for up to four hours PA

More than 13,000 people a day are visiting the Natural History Museum to see the four-metre- (13ft-) tall model, which looks, moves and even smells like a T. rex.

Youngsters, many of whom are on school half-term holidays, are queuing with parents for up to four hours to see the exhibit.

The animated dinosaur was unveiled a week ago but will be on show for the next two years.

Face-to-face

Japanese technicians have been working with the museum for the last 10 years to bring visitors face-to-face with the giant predator, which roamed the Earth more than 65 million years ago.

Even with our experience of dinosaurs, this is unprecedented

Dr Neil Chalmers, museum director

When approached, the three-quarter size model gives out a roar. It is surrounded by a pre-historic boggy smell.

Museum director, Dr Neil Chalmers, said they had not expected so much interest. "Even with our experience of the popularity of dinosaurs, this is unprecedented," he said.

"We are delighted that so many visitors have come to see the T. rex but we do recognise that for the fist two weeks of opening it is going to be very busy and queues may be long."

Realistic odour

But some visitors said that it was worth the wait. Lesley Rutter, 42, travelled from Bedford with her three children and two nieces to see the dinosaur.

The lifelike T. rex stands four metres tall

"They had told us that it would take two hours to get into the museum and a further hour to see the T. rex," she said. "But I have children with me aged six to 15 and I think it is worth it as there is something inside for all ages."

"Dragon's Breath" and "Swamp" are two of the oils which help provide the realistic odour.

"Whenever T. rex opened its huge mouth, a strong aroma of rotting flesh would certainly have filled the air," said Dr Angela Milner, the museum's dinosaur expert.

The smell can be bought in bottled form by those visitors that want to recreate the Jurassic Park atmosphere in their homes.

The robot is an evolution of the machine that first terrified and wowed museum visitors two years ago. A central computer and complex electronics drive hundreds of air pistons under the rubber creature's skin.

The museum and Kokoro, the Japanese animatronics company who developed the technology, hope to sell similar beasts to science and dinosaur galleries around the world. This particular T. rex model can be bought for �220,000.