Feb.26 (GMM) The operators of Barcelona's formula one circuit on Monday admitted that security has been tightened since the racism scandal erupted three weeks ago.

Lewis Hamilton seemed unperturbed as he drove to the top of the time sheets, but a Circuit de Catalunya spokesman revealed that much effort has been put into ensuring that the bigotry of some Spanish supporters is never again seen.

"We have made some changes," he told Britain's Guardian newspaper, after the FIA warned that a repeat of the incidents could cost Spain its two grands prix.

The spokesman said fans' banners and clothes are being checked this week, while the grandstand opposite the McLaren garage and the roof above the team's pit area is closed, and access in the paddock has been reduced by the erection of barriers.

"We want McLaren and Hamilton to be comfortable," he insisted.

Germany's Bild newspaper revealed that extra security people are on duty in the paddock.

"It is a purely precautionary measure," the spokesman said.