Red Bull team principal Christian Horner has called for clarity about future Pirelli tyre tests in Formula 1.

Pirelli's 1,000km test in conjunction with Mercedes in Barcelona last month has upset many of the teams as the Silver Arrows' current car was used.

The FIA has referred the matter to its international tribunal after a protest was lodged by Red Bull and Ferrari.

"The lack of transparency is disappointing, that you get to learn these things second hand, so it is important there is transparency," said Horner.

"If a supplier has issues then it needs to obviously deal with them, but when all entrants are supposedly equal, it's only right and proper that information is made transparently clear."

This weekend F1 is in Canada and you can follow live updates of both today's qualifying and tomorrow's race here on Sports Mole.