McLaren boss Zak Brown intensified his campaign against multi-team ownership structures in Formula 1 by formally urging the FIA to crack down on alliances between rival teams.

In a letter sent to the governing body, Brown called for the elimination of “A/B-style relationships” as well as any ownership links, strategic partnerships or forms of influence shared between competing entries on the grid.

Instead, he argued that Formula 1’s current financial stability under the cost cap means teams should now operate as completely independent competitors.

“There is a real concern that the sport risks taking a step backwards in terms of integrity and fairness, at a time when the regulatory framework has been designed – with significant collective effort – to move in the opposite direction,” Brown wrote.

We need to eliminate any further alliances

The McLaren CEO pointed to examples he believes show how linked teams can influence championship outcomes. Among them was the 2024 Singapore Grand Prix, where Daniel Ricciardo took the fastest lap for Racing Bulls, denying McLaren’s Lando Norris an extra point during his title fight with Max Verstappen.

Brown also raised concerns over the speed at which staff can move between affiliated teams compared with the restrictions faced by independent outfits.

He argued that shared facilities, software systems and technical infrastructure create competitive advantages not available to standalone teams.

“We need to eliminate any further alliances, whether through ownership, strategic participation or any other equivalent form of control or influence, and we need to work together quickly to start the process of unwinding those already established to ensure that the future integrity of the sport is not compromised,” Brown said.

Brown stressed that his position was not targeted at any one team and praised the current health of the championship: “I think the work that the FIA and Liberty have done to create 11 healthy teams, in a cost-controlled environment, has created the most competitive era of Formula 1 ever."

Brown praises Formula 1 growth but wants reform

Brown believes resolving the ownership issue would strengthen the championship even further: “We believe that, by addressing this remaining structural issue, Formula 1 will be set on an even stronger course, will continue to thrive and be the best the sport has ever been.

"We just need to make sure we bring total parity and integrity to the sport in every aspect. I am confident we can achieve that together,” he explained.

Speaking ahead of the Miami Grand Prix, Brown reiterated that his concerns apply across the grid rather than towards specific rivals: “I don’t think it’s healthy for the sport. But it’s not personal or towards any one team or individual."

FIA president Mohammed Ben Sulayem has previously acknowledged that the governing body is reviewing ownership structures and their impact on sporting fairness, while also indicating support for greater independence between teams.