Four years later, Allison stepped back from full-time F1 by taking on the newly created role of chief technical officer, with a more over-arching brief of the company's technical division as a whole.
With Mercedes struggling to get to grips with the new ground-effect aerodynamic regulations that were introduced at the start of 2022, Allison returned to the role of technical director in April last year.
With Allison's commitment to the TD position reinforcing the technical leadership ahead of the major rule changes for 2026 when a new power unit will be introduced, he said: “F1 has brought me a lot of good fortune, but none greater than answering Toto's call to join Mercedes in 2017.
“It is a great privilege to continue this adventure, working alongside brilliant colleagues and fighting together for championship success.”
Declaring himself “thrilled” at securing the services of a man he describes as “the most impressive technical leader in our sport,” team principal Toto Wolff added: “His gladiator spirit, along with his knowledge, experience, and determination, make him second-to-none.
“His influence and impact, however, goes so much further than that.
“Since joining in 2017, he has been a key ally and sparring partner for me personally. We can challenge each other openly and honestly; an embodiment of the ‘tough love' culture of the team that is vital in helping us all perform at our very best.
“Most importantly, though, James is a true friend you can rely on, not only in times of success but in difficult moments too.
“It has been a pleasure to work with him over the past seven years and I look forward to doing so for many more to come.”