Alpine team principal Oliver Oakes has left the team less than a year after being appointed to the role.
A statement by Alpine on Tuesday said Oakes had resigned and that the team had "accepted his resignation with immediate effect".
The team said Flavio Briatore would continue in his role as executive adviser and would now also cover the duties Oakes had performed.
No explanation was given for Oakes' departure. The team said no further comment would be made and Oakes declined to comment when contacted.
A source told BBC Sport that it was Oakes' decision to leave. Others said that it came as a surprise inside the team.
Oakes, who moved to Alpine from his Hitech team that competes in the junior categories, was widely considered within F1 to have little power at the team, with former Renault team boss Briatore the real controlling force.
Briatore's controversial return to F1 as a team leader 15 years after he was found guilty of fixing the 2008 Singapore Grand Prix as Renault team boss was orchestrated by Renault Group chief executive officer Luca de Meo in July last year.
Oakes' departure comes just a day after it emerged that Alpine were poised to drop Australian Jack Doohan after just six races this season and replace him with Argentine former Williams driver Franco Colapinto.
