Christian Horner is under investigation by Red Bull following an accusation of “inappropriate behaviour”.

The PA news agency understands the allegation has been made by another member of staff for the British-based Formula One team which last year carried Max Verstappen to his third consecutive world championship.

Horner, 50, who has been Red Bull team principal since 2005, will remain in his role during the investigation. He strongly denies the accusation.

Horner said: “I completely deny these claims.”