Formula One has banned from next week's Singapore Grand Prix all radio communications that help improve the performance of the car or driver in a move that could add another twist to the title battle between Nico Rosberg and Lewis Hamilton.
A technical directive has been issued to teams by the governing FIA to remind them of the wording of article 20.1 of the 2014 sporting regulations.
This states that "the driver must drive the car alone and unaided."
The FIA said no radio conversation from pit to driver may include any information "related to the performance of the car or driver" and also cited article 8.5.2 of the technical regulations stipulating that "pit to car telemetry is prohibited."
The rules apply to all track sessions during a grand prix weekend and would include warning drivers about fuel consumption and the condition of a car's brakes and tyres.
Information about traffic and telling drivers when to make their pitstops would remain permissible as would team orders regarding overtaking and general messages between the pit and driver.
The change could reward those drivers with a more intuitive style and who are good at keeping on top of all the in-car readings.
The move comes after a marked increase in radio traffic this season following the introduction of the new V6 turbo hybrid power units and a greater emphasis on fuel saving, tyre management and energy recovery.
Race engineers have increasingly been advising their drivers how to gain a track advantage or vital fractions of a second in performance, with Mercedes team mates Rosberg and Hamilton no exceptions.
Retired four times world champion Alain Prost is one of those who has advocated just such a clampdown, telling autosport.com that Formula One was sending out literally the wrong messages.
Drivers have already said that the cars are easier to drive than previously.
The counter-argument is that Formula One is a team sport, with teams fighting for the constructors' championship as well as the drivers' crown.