Christian Horner has revealed what 
Daniel Ricciardo said to him when the Australian revealed he was going to leave 
Red Bull for 
Renault.
 Horner told Motorsport that 
Ricciardo said it was not because of 
Red Bull as a team but instead the reason lay at the door of the now 
Renault driver.
"As I said, he made that classic break of 'it's not you, it's me'. ‘I think I really needed to take on a new challenge." said Horner.
Despite 
Ricciardo stating otherwise, the Englishman does feel 
Max Verstappen’s development had a part to play.
Verstappen struggled in the early parts of 2018 but established himself as 
Red Bull’s main man after the mid-season break, earning himself two wins for the year.
 "I think he was also worried about his value in the team in relation to the evolution of Verstappen, he was not sure at all with Honda at that time, although I think he has started to see the fruits of what we were talking about then.
"The number one driver in this team is the one who is ahead on the track, the rule is simple.
"Mexico was the first time that Daniel overcame Max from Monaco, Verstappen's performances have been huge in qualifying and it has been a difficult season for Ricciardo who has had to face the tremendous evolution of Max.” Added Horner.