Red Bull sacked Christian Horner, Formula One's longest-serving active team principal and one of the most successful of all time, and replaced him on Wednesday with Racing Bulls' Laurent Mekies. Horner,

Red Bull’s Formula 1 team is changing team directors for the first time since it was founded 20 years ago, after Christian Horner's sacking sent shockwaves through the sport on Wednesday.

Red Bull’s performance has slumped this year after the departure of designer and engineer Adrian Newey, a key figure in the team’s success.