Red Bull still seeking clarification about the legality of Mercedes's rear wing

Although motor racing's governing body has twice ruled that the DRS-activated F-duct - which helps stalls the front and rear wings for a straight-line speed boost - is fully legal, that has not stopped attempts by Red Bull Racing and Lotus to get it outlawed.

Red Bull team principal Christian Horner told Sky's 'F1 Show' that he expected further progress on the matter to take place ahead of the Chinese Grand Prix, when a ruling from the head of F1's technical department Charlie Whiting is expected.

"Charlie Whiting, the technical delegate, has been taking it all into consideration and there were several discussions with him over the [Malaysia] weekend," explained Horner. "I think he wanted to have a think about it and of we'll of course respect his position when he makes that clear to us in China.

"Then the teams are faced with alternatives. Either accept it and get on it and maybe look at your own solution if that fits your car. You've got the opportunity to protest if we were to feel, or any other team were to feel, that we didn't agree with Charlie's interpretation."

Although Red Bull's attempts for clarification over the matter have not yet resulted in a change of stance from the FIA, Horner says it is continuing its push because it does not want to embark on an expensive development programme only for the concept to be outlawed in a few race's time.

"As with all devices like this, it's how it interacts with the rest of the car," he said. "Of course I'm sure all the designers certainly at the front end of the grid have been looking at how the device works, how you would incorporate it into your own design.

"But before we pursue constructing parts and expense to it, for us it's quite important to know that, yes, it's going to be permissible for the rest of the year. And quite often we see technical clarifications come out that deem things to be not in compliance with the regulations."