McLaren boss Ron Dennis has cast doubt on Max Mosley's motives for quitting as boss of motorsport's governing body.
Dennis and Mosley have fought many battles down the years
Mosley said he has decided to step down from his role as FIA president in October because he has become tired of the job and Formula One politics.
But Dennis said it was because his plans to change the structure of the FIA were defeated last week.
"I don't think Max's reasons for leaving the FIA are consistent with what he says," Dennis said.
"I think you should look to the [FIA] world council meeting and try to explore fully what happened there."
Mosley was defeated in a vote about karting at last Wednesday's meeting, while other proposals to divide the role of the FIA president were shelved when it became clear there was opposition.
Mosley has rejected Dennis' claims.
"I've seen it reported occasionally in the press as though something was significant but it wasn't, it's a completely trivial matter," Mosley said.
Dennis also took umbrage at the FIA president's categorisation of the F1 team owners as a bunch of ditherers, who agree something at meetings and then go away and change their dates.
"There were many things that were said by Max that were misleading and not accurate," said Dennis, who has had many battles with Mosley down the years.
"He portrays the teams as not being responsive in so many areas which is just not accurate.
"It is quite true that some team principals rejected qualifying and changed their positions during the course of the F1 commission (meeting) but this was preceded by a very clear statement from Max that he did not want this qualifying to be introduced."
Dennis also laughed off a remark from Mosley that one team owner was "not perhaps the sharpest knife in the box", a remark that was widely believed to refer to Dennis.
Dennis said Mosley's comments had been "not too presidential and certainly not too factual".