Williams has turned down Ferrari's request for Michael Schumacher to test the Italian team's 2009 contender ahead of his return to the grid at Valencia later this month.

Last week, Ferrari wrote to its rival teams seeking permission for the German to test the F60 claiming that F1 cars have changed dramatically since he retired from the sport at the end of 2006.

However, while the other teams are widely believed to have agreed to Ferrari's request, Williams has said no, claiming that Maranello outfit should have called on one ifs two test drivers - Luca Badoer and Marc Gene - to replace Felipe Massa.

In a brief statement issued today, the Grove outfit said:

"While we welcome Michael Schumacher back to Formula One, the fact is any form of in-season circuit testing is strictly prohibited, a regulation clearly laid out by the FIA and adhered to by all of the teams.

"It was for this reason Jamie Alguersuari, who drove an F1 car for the first time in Hungary, did not have the opportunity to familiarise himself with the Toro Rosso before he made his race debut.

"Williams sees no distinction between Alguersuari's situation and Schumacher's and feels any deviation from the rule would create a precedent for the future.

"In a similar situation, Williams would unhesitatingly use its current test driver. For the sake of consistency and fairness, therefore, we oppose Ferrari's proposal to test ahead of the European Grand Prix."

Ironically, Williams test driver Nico Hulkenberg is managed by Willi Weber, who also manages Schumacher.

Schumacher has already completed 67 laps of the Mugello circuit using a revised 2007 car.

While all the other FOTA teams are understood to have agreed to Ferrari's request, Williams which is no longer part of the teams' alliance is the only team to officially reject the request, while Force India, also no longer part of FOTA, has yet to respond.