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The engineers who have designed the official football for the 2010 World Cup have hit back at criticism of their ball by some players.

Fabio Capello said his players gave the new ball bad reviews, with some players saying it moves too quickly.

And goalkeepers have claimed the new Jabulani ball is difficult to handle.

But engineers at Loughbrough University claim that their tests show it is the most "consistent" football ever manufactured.

The football that former England international Geoff Hurst belted into the goal in the 1966 World Cup final was made from 18 pieces of leather, stitched together and fastened with laces.

The new World Cup football is made from just eight pieces of shaped synthetic material glued tightly together.

The result - for the first time in football history, say the manufacturers - is an undistorted, perfectly spherical ball.

But some players say it moves too quickly, and a number of goalkeepers say it is difficult to handle.

The engineers who helped design the ball, called the Jabulani, say it should be the most consistent football ever made.

Dr Andy Harland at Loughborough University used a robot to kick the ball.

His set up is able to reproduce corners, free kicks, passes and shots on goal - even more reliably than David Beckham.

Shining example

"Fundamentally, what we are trying to achieve is a ball that is very consistent that allows the very best players in the world to express their skills," he says.

"So we're not looking for a ball that behaves unpredictably which would benefit a player that's not skilful. We want a ball that is very consistent that allows the best players to shine."

His robot tests, which were supported by the ball's manufacturer Adidas, showed that the Jabulani was better than previous World Cup balls. It flew through the air more smoothly and hit its targets more reliably.

Dr Harland's colleagues used a wind tunnel to aerodynamically design the grooves on its surface, which guide the ball as it flies through the air.

In the past, their positions have been determined by the ball's natural seams but the Jabulani doesn't have any seams so, according to Dr Martin Passmore of Loughborough University, engineers can put the grooves where they like.

"What we've tried to do with the inclusion of grooves," he explained, "is to make sure that the ball looks much more symmetrical in flight, so it flies in a much more controlled way and gives the control back to the player to get it to do what they want to do."

Young boys at the Kingston-Upon-Thames Little League say the new ball is "awesome".

But it's too expensive for their coach and one of the league's organisers, Andrew Standford.

His practice footballs cost £5 and match balls retail for £15. By comparison, the Jabulani costs more than £60.

For Mr Standford, the production of a new ball is as much about marketing as it is about improving the quality of footballs.

"Every new World Cup, there's a new football out and each time it seems a little bit more expensive. It does feel good and it does play well but it is expensive for what's just a football."

But researchers at Loughborough University say the ball is well worth the price. The gripes by some players, he says, are possibly a result of some of the World Cup venues being located at high altitudes in South Africa, rather than any problem with the ball.

At higher altitudes, the air is thinner and so the ball moves faster. Dr Passmore thinks that the players will soon get used to the conditions. So has he helped to create the perfect ball?

"I don't know if there's such a thing as a perfect ball. And I don't think it's entirely clear what you'd want from a perfect ball. Maybe a perfect ball would be one that I could use to score the winning goal in the World Cup."