Toto Wolff and Christian Horner's explosive row: 'Should keep his mouth shut'

The fallout following last season's Abu Dhabi Grand Prix continues to dominate the headlines in Formula 1 as new audio from the race sparks fresh controversy. Race director in the season finale in December, Michael Masi, can be heard reacting to Red Bull's suggestions as to how to end a safety-car period. Red Bull sporting director Jonathan Wheatley urges Masi to get the lapped cars out of the way so that "we've got a motor race on our hands." Masi replies: "Understood"

Later, when Toto Wolff of Mercedes fumed down the microphone at Masi's decision to let lapped cars pass the safety car, the race director replied: "Toto, it's called a motor race, OK?".

A spokesman for the FIA said: "We are aware of this and it is part of the investigation."

The dramatic events of last season's finale epitomised the intense rivalry between Red Bull and Mercedes, their drivers Max Verstappen and Lewis Hamilton, and the team bosses Horner and Wolff.

Horner has become a staple of Formula 1 having worked in his role as Red Bull Team Principal for 17 years.

Meanwhile, Wolff and his Mercedes team have dominated since 2014, winning every Constructors' title in that time.

In July last year, their rivalry became apparent when Horner branded Wolff a "control freak" and suggested a month prior to this that the Austrian "should keep his mouth shut" in a row over regulations.

In June, Horner said: "If you are picking on one end of the car, you have to look at the other.

"You can't look at one part in isolation and say: 'Oh, that set of rules only applies to that element on that car'.

"I think if I was Toto, with the front wing he's got on his car, I'd keep my mouth shut."

Wolff responded at the time: "Christian is a bit of a windbag who wants to be on