As debate continues as to why Norbert Haug and Mercedes-Benz have parted company, Michael Schumacher, who worked with the German at the beginning and end of his career, has paid tribute to the man.

"Since I entered professional motorsport, Mercedes and Norbert Haug together were part of it, so this step will mark a big break," said the seven-time champ on his personal website.

"We spent a lot of years together, being sporting combatants or allies, and Norbert has always been into this with full enthusiasm and wholeheartedly. He was living motorsports, and him leaving will tear a massive hole in both our sport and our team."

Despite speculation that it was Niki Lauda that edged him out, we understand the Austrian was as shocked as anyone when Haug made his announcement at the end of a board meeting last Tuesday, the first under Lauda's stewardship as Chairman.

While Haug has taken the blame for Mercedes poor season, ironically having claimed its first win since its return to the sport in its own right, others believe it should have been Ross Brawn who should have fallen on his sword.

According to some sources, Haug and Brawn were at odds over a number of issues, a situation not helped by the fact that the team's Brackley HQ is effectively 'Brawn territory'.

Though Haug is seen as the man who brought Michael Schumacher back to F1, our sources claim he felt the seven-time champion should have spent a season with a "customer" team before joining Mercedes. We also understand that Haug was opposed to the double DRS system claiming it was viable in long environs but disturbed the diffuser at shorter circuits.

Indeed, we understand Haug argued that Mercedes should adopt the Red Bull philosophy that outright speed was not the answer but agility around the circuit was, but that on almost every point he was overruled by Brawn.