Toto Wolff calls for transparency in Red Bull’s Christian Horner investigation

Christian Horner in Bahrain for the opening day of testing (Darko Bandic/AP)

Mercedes boss Toto Wolff has called for Red Bull’s investigation into Christian Horner to be transparent – and said the controversy is “an issue for all of Formula One”.

Horner is under investigation by the racing team’s parent company Red Bull GmbH following a claim of “inappropriate behaviour” by a female colleague.