Mercedes bid farewell to eight-title engine era as F1 braces for 'biggest ever' rule change

Formula 1's racetracks have fallen silent and the 2025 cars have been wheeled into storage — but inside the sport's top-secret factories, the pressure has never been greater. That contrast sits at the heart of A Clean Sheet, an episode of the BBC's Back at Base series under the Chequered Flag banner, which goes behind closed doors at a time when revised rules for 2026 are reshaping the cars and redefining what powers them.

The programme describes a winter like never before for the hundreds of staff working back at base, with the sport's engine suppliers facing a period of major transition as they build for F1's new era.

End of an era at Brixworth

Before diving into the future, the team at Brixworth — the home of Mercedes High Performance Powertrains — are marking the end of an era. It was here that the engine which drove Mercedes to eight straight Constructors' Championships between 2014 and 2021 first came to life.

Brixworth boss Hywel Thomas has planned a very special celebration to mark the end of this engine cycle, and the programme's expert guides, Sarah Holt and Holly Samos, were there to join in the festivities. Thomas and his team have also been developing the new engine that will power Mercedes and three other teams on the grid in 2026.

Allison daunted by 'biggest ever' change

Parallel work is under way at Brackley, where Mercedes Technical Director James Allison is overseeing all other aspects of the new season's car design. The British engineer brings more than three decades' experience in F1 — but even he is a little daunted by what he calls the "biggest ever" rule change in the sport's history.

Drivers down tools — for now

While the work intensifies inside the factories, it is, in contrast, time for the drivers to unwind. Italian Mercedes star Kimi Antonelli is heading home to spend some time with his family and friends, while Haas driver Ollie Bearman is holidaying in the Maldives before spending Christmas with his family in Monaco.

Haas pulling together for 2026

Back at base, the Haas team are hard at work preparing for F1's new era in 2026 — and that means both sides of the garage are collaborating too. Laura Muller, who works alongside Esteban Ocon and is an F1 trailblazer as the sport's first female race engineer, has just wrapped up her first season on the pitwall. Like Bearman, she knows the experiences of 2025 will help her navigate what lies ahead.

Bottas counting down to Cadillac bow

F1 race-winner Valtteri Bottas is preparing for his return to the grid with the Cadillac Formula 1 team in South Australia. But even in an idyllic spot for winter training, the Finnish favourite is already counting down to pre-season testing and the first race in Melbourne, Australia, as he starts the next chapter of his F1 career.

How to listen

F1: Back at Base is an IMG Production for the BBC, hosted by Rosamund Pike, with co-hosts and executive producers Sarah Holt and Holly Samos. The episode is available on BBC Sounds.