Ross Brawn: Lack of trust with Toto Wolff and Niki Lauda led to Mercedes exit

Ross Brawn (left) alongside current Mercedes boss Toto Wolff in 2013

Ex-Mercedes team principal Ross Brawn says a breakdown in his relationship with current bosses Toto Wolff and Niki Lauda was behind his departure in 2013.

The Brawn team won both world titles in 2009 - having been salvaged from the failed Honda operation - before being sold to Mercedes in 2010.

"People were imposed on me who I couldn't trust," Brawn says, in a new book due to be published next month.

"I never knew really what they were trying to do."

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The 61-year-old Briton, who masterminded Michael Schumacher's seven world titles at Benetton and Ferrari, added: "Niki would tell me one thing, then I would hear he was saying something else."

Brawn's version of events is set out in 'Total competition, lessons in strategy from Formula 1', an advance copy of which has been seen by Reuters.

Brawn said he discovered early in 2013 that Paddy Lowe, now technical head at Mercedes, had been signed from McLaren - a move that at the time prompted speculation over Brawn's future.

He eventually left the team at the end of the 2013 season after failing to agree the scope of his future role. That left Mercedes to be run in tandem by their two executive directors, Wolff and Lowe, along with non-executive chairman Lauda.

"When I challenged Toto and Niki, they both blamed each other," said Brawn. "I met them together to have it out with them and they both pointed to each other.

"Even with Paddy Lowe, I was never quite sure - he was quite happy to jump in and take my job.

"I couldn't trust those people so I saw no future unless I was willing to go to war and remove them."

Mercedes' current drivers, Lewis Hamilton and Nico Rosberg, were signed during Ross Brawn's time as team principal

Brawn also claimed Wolff made critical comments about him in a taped conversation with former F1 team boss Colin Kolles.

"He said that I was resting on my money now. I had got all this money and I wasn't interested in the team any more and I wasn't motivated and I wasn't doing this, I wasn't doing that. That the team needed a fresh impetus," said Brawn.

"So I was beginning to deal with people who I didn't feel I could ultimately trust - people within the team who had let me down already in terms of their approach."

Wolff, Lauda and Lowe were not immediately available for comment.

Mercedes driver Nico Rosberg leads team-mate Lewis Hamilton by 33 points in the drivers' standings heading into this weekend's US GP in Austin, Texas.

Mercedes wrapped up a third straight constructors' title at the previous round in Japan.