Seven of the 10 F1 teams have expressed their "surprise and shock" at the FIA's private settlement with Ferrari following an investigation into the team's 2019 engine.
Ferrari's power unit used last season was the subject of much speculation after rival teams raised concerns about the Italian team's level of superiority in straight-line speed.
Last week, F1's governing body the FIA announced they had "reached a settlement" with the Italian outfit after long-running technical investigations into the controversial engine.
Details of the settlement were kept private and now Ferrari's rivals have issued a collective response in which they questioned the FIA's integrity and demanded "proper disclosure".
Mercedes, Red Bull, McLaren, Renault, Racing Point, Alpha Tauri, and Williams - the seven teams on the grid who are not powered by Ferrari engines - all released identical statements yesterday.
The statement said: "We, the undersigned teams, were surprised and shocked by the FIA's statement of Friday 28 February regarding the conclusion of its investigation into the Scuderia Ferrari Formula 1 Power Unit.
"An international sporting regulator has the responsibility to act with the highest standards of governance, integrity, and transparency.
"After months of investigations that were undertaken by the FIA only following queries raised by other teams, we strongly object to the FIA reaching a confidential settlement agreement with Ferrari to conclude this matter.
"Therefore, we hereby state publicly our shared commitment to pursue full and proper disclosure in this matter, to ensure that our sport treats all competitors fairly and equally. We do so on behalf of the fans, the participants, and the stakeholders of Formula One.
"In addition, we reserve our rights to seek legal redress, within the FIA's due process and before the competent courts."Ferrari during testing in Barcelona last week (Image: ALEJANDRO GARCIA/EPA-EFE/REX)
This incredible development comes after teams including Lewis Hamilton's Mercedes and Red Bull made clear their suspicions over the way Ferrari operated their power unit last season.
There were concerns that Ferrari exploited a grey area in the rules to increase their fuel flow and boost performance.
Ferrari drivers Charles Leclerc and Sebastian Vettel combined to secure six consecutive pole positions and three victories before the FIA closed the potential engine loophole ahead of the US Grand Prix in November.
They subsequently struggled for pace in America, as well as the remaining two races of 2019 in Brazil and Abu Dhabi, and appeared to suffer several power-unit problems in pre-season testing last month.
Ferrari have always maintained their innocence and were subjected to several in-season investigations during the course of the 2019 campaign.
The FIA insisted in their statement issued on Friday that they had concluded a "thorough technical investigation" but "the specifics of the agreement (reached) remain between the parties".
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