Lewis Hamilton "wasn't satisfied" despite all the success he has had with Mercedes, according to one of the team's former top bosses.
The Silver Arrows became the team to beat as they adapted best to new car regulations in 2014. And they made the most of it by launching a dynasty which saw them take eight consecutive constructors' titles.
Hamilton was the spearhead of that success. Nico Rosberg and Valtteri Bottas also made significant contributions, but six of the Brit's seven drivers' championship successes came in that period.
