Race stewards at Monza have fined McLaren $50,000 (£25,000) for using an 'illegal' gearbox in the Hungarian GP.
The new lightweight gearbox had been run without being subjected to the mandatory crash test and therefore breached article 16.1.2 of the F1 technical regulations, which state that "any significant modification introduced into any of the structures tested shall require that part to pass a further test."
After hearing evidence from Engineering Director Paddy Lowe and Team Manager Dave Ryan, the stewards in Monza ruled that the Woking team had broken the rules.
In a statement issued earlier this afternoon, McLaren claimed that they had informed Charlie Whiting of the decision to run the lightweight gearbox a week before the Hungarian GP. Based on their own computer models however, the team felt that the difference between the gearboxes was not enough to justify a further crash test, they were wrong.
In a statement issued this evening, the stewards claimed McLaren had; "deprived the FIA of the opportunity before the race to consider the changes made and require impact testing to be carried out before use.
"Had such information been imparted in due time the tests could have been satisfactorily completed prior to the Hungarian Grand Prix, such that their use at this event would have been without criticism."
The stewards censured McLaren, noting that the British team had reverted to its 'old' gearbox in Turkey, before the lightweight version passed the impact test.
"The view of the stewards is that the components having been satisfactorily tested indicate that the cars complied with the technical configuration required when they raced in Hungary."
This is the latest episode in a summer of discontent for the Woking team, which now faces another meeting of the World Motor Sport council next Thursday, following the FIA's announcement that it has new evidence relating to the ongoing spy saga.
In Hungary, the British team failed to score constructors' points - despite finishing first and fourth - following the qualifying incident involving drivers, Lewis Hamilton and Fernando Alonso.