As teams seek ever more ingenious ways of pushing the rules to the very limit, and then some, the FIA has sent out a warning relating to one such suspect device.

Following suggestions that Red Bull, and one or two others, might be using a system - thought to involve a ratchet - which alters the ride height on the car, the FIA has written to all twelve team clarifying the rules.

"Any system, device or procedure, the purpose and/or the effect of which is to change the set up of the suspension whilst the car is under parc ferme conditions will be deemed to contravene Article 34.5 of the F1 Sporting Regulations," it read, adding that; "any self levelling damper system is likely to contravene (article) 3.15 of the technical regulations."

Article 34.5 states that a driver must start the race from the pit lane if any changes are made to the suspension of his car while it is held under parc ferme, while Article 3.15 refers to aerodynamics.

Last month, McLaren boss, Martin Whitmarsh, pointed the finger at a number of rival teams, including Red Bull, suggesting they were breaking the rules. "There's evidence there are ride-height control systems which many people thought weren't permissible," he told the BBC.

"It looks like Red Bull and some other cars are able to run lower in qualifying than you would expect if they're then going to fill the car with fuel afterwards," he added. "As you can imagine, we're working quite hard on those systems now.

"The original rulings suggested such systems wouldn't be allowed on cars but we're seeing some cars which seem to have them. We've got to have them fitted as soon as we can, hopefully by China we'll have something on the car."

Ironically, active ride-height systems were originally pioneered by Lotus, which - under an entirely different guise - has 'returned' to the F1 grid this season. Used to superb effect by Williams in the early 90s, such systems were subsequently banned in 1993.