Red Bull Formula One team boss Christian Horner is under investigation following an accusation of "inappropriate behaviour". Dutch newspaper De Telegraaf reported the allegation was made by another member of staff for the British-based team, which last year carried Max Verstappen to his third consecutive world championship. Horner, 50, who has been Red Bull team principal since 2005, strongly rejects the accusation. "After being made aware of certain recent allegations, the company launched an independent investigation," Red Bull, the Austrian energy drinks firm which owns the F1 team, said in a statement.