Hamilton not using KERS at Silverstone

Only three cars were fitted with KERS systems as the pitlane opened for morning practice at Silverstone on Friday.

Ferrari is persevering with the controversial energy recovery technology, but other KERS users BMW and Renault have moved away from their systems in recent races.

Until now, Mercedes' unit, fitted to the works McLarens, has been regarded as the best in use, and Lewis Hamilton and Heikki Kovalainen's cars have been fitted with KERS for the entire season so far.

But at Silverstone, a McLaren spokesman on Friday morning confirmed reports that Hamilton's car is not using KERS for the three hours of opening day practice.

It is believed that, despite the high average speed of the Silverstone layout, the lack of many hard braking zones means that KERS is on the limit in terms of keeping the batteries fully charged.

"We want to do a direct comparison," Hamilton's teammate Heikki Kovalainen, whose MP4-24 will be fitted with KERS on Friday, said.

The Finn believes KERS will still be an advantage, even at Silverstone.

"Our simulation shows a fairly consistent advantage at each track of approximately three tenths," said Kovalainen at the scene of the British grand prix.