The velociraptor, whose speed and ferocity was highlighted in the film "Jurassic Park", reached 24 mph while the T-rex could muster speeds of up to 18 mph, the study published in the Royal Society's Biological Sciences showed.

"Our research, which used the minimum leg-muscle mass T-rex required for movement, suggests that while not incredibly fast, this carnivore was certainly capable of running and would have little difficulty in chasing down footballer David Beckham, for instance," said Phil Manning, a palaeontologist at the University of Manchester, who worked on the study.

The smallest dinosaur -- the Compsognathus -- could run nearly 40 mph, about 5 mph faster than the computer's estimate for the fastest living animal on two legs, the ostrich.

A top human sprinter can reach a speed of about 25 mph.

The researchers used a computer model to calculate the running speeds of the five dinosaurs that varied in size from the 3-kg (6.6 pound) Compsognathus to a six-tonne Tyrannosaurus.

They fed information about the skeletal and muscular structure of the dinosaurs into the computer and ran a simulation tens of millions of times to see how fast the animals moved, said William Sellers, a zoologist at the University of Manchester, who led the study.

They checked their method by inputting data of a 70-kg human with the muscle and bone structure of a professional sportsman and found the computer accurately spat out a top running speed just behind T-rex's pace.

"People have estimated speeds before but they have always been indirect estimates and hard to verify," Sellers said. "What we found is they were all perfectly capable of running."

Looking at how these ancient animals lived and died out is also important in trying to predict how modern day species may cope with future climate change, Sellers added.

This study helps to build a biological picture that scientists can use to better understand how dinosaurs adapted to changes in the weather just before they went extinct some 65 million years ago, he said.