Williams still torn over drivers

Heidfeld was called into to test for Williams at Jerez twice before the Christmas break and recorded a time quicker than that of the team's regular test driver Pizzonia. But the Brazilian impressed the team when he stood in for the injured Ralf Schumacher and is known to rated highly by key staff at Williams.

"The lap was a one-off," explained Williams, "and not enough to make a choice from. Antonio Pizzonia's long runs were fast and very consistent and we want to be fair to both of them.

"We have had the good fortune through unfortunate circumstances to race with Antonio last year and every race he started he did a better job than the previous one. Nick's arrival was unexpected because we were comfortable to have Antonio for 2005. But then we thought we should look at other drivers in case one was faster."

When pressed on when a decision might be made on the identity of the team's second driver Williams said: "Our present plan is to be fair to the team and the two drivers and give them both a fair chance to demonstrate what they can do for the team.

"There will be two or three more tests so by the launch of the car at Valencia at the latest we want to have made a decision."

Williams was talking at the unveiling of a three-year sponsorship deal with the Royal Bank of Scotland which is believed to be worth US$38m per season for the team. The agreement makes RBS Williams's second largest sponsor behind HP.