By sacking Christian Horner, Red Bull has made a big change to try to return to F1 winning ways. But there are other steps it must take, too

Christian Horner spent large parts of his last 18 months at Red Bull clinging onto his job. He took public criticism from Max Verstappen 's dad, Jos. He faced allegations of inappropriate behaviour from a female colleague, which he was later cleared of. And he was central in rumblings of friction between key figures at the top of the F1 team.