A return to Formula 1 will be difficult for former Red Bull team principal Christian Horner because he has "broken quite a lot of glass", says ex-Mercedes rival Toto Wolff. A return to Formula 1 will be difficult for former Red Bull team principal Christian Horner because he has "broken quite a lot of glass", says ex-Mercedes rival Toto Wolff. Horner was sacked in July after 20 years in his role following declining form... [2395 chars]