Christian Horner has revealed the surprising cost Formula 1’s new rear wing deflection tests will have on Red Bull.

The rear wing on the RB16B has been a hot topic in recent races after it was seen to flex under load during the Spanish Grand Prix.

Technical regulations state that, aside from the DRS flag, bodywork must be fixed, with deflection tests designed to confirm legality.

Red Bull’s design passes those tests but can been seen to deform at high speed, a point the likes of Mercedes and McLaren believe is a breach of the regulations.

Alpine, Alfa Romeo, and Ferrari all have similar wings, however they are not currently in with a shot of the world championship, while Red Bull leads the constructors’ competition for the first time since 2013.

In response to the situation, the FIA has issued a technical directive, effectively clarification on the existing rules in which it states the deflection test will be ramped up following the Azerbaijan Grand Prix.

There will also been a honeymoon period during which teams will be afforded a little extra leeway as they work to remedy their designs.

According to Red Bull, that time is needed as changes to its rear wing will take time to implement.

Both Mercedes and McLaren are deeply unhappy with that situation, with the former suggesting that it will protest Red Bull should it head out on track in Azerbaijan with an unchanged wing.

“Obviously there are weight considerations, it’s a single pylon rear wing,” Horner, Red Bull’s team principal, began.

“There are so many things to take into consideration, so there has to be a lead time with these things.

“It’s not just the simplicity of just adding more weight to the car.”

Mercedes boss, Toto Wolff, has claimed that his team raised the issue of flexible rear wings with the FIA last year, but no action was taken.

Now locked in battle for the title, which this year comes with the added limiting factor of the budget cap, the issue has again raised its head – thanks largely to comments made by Wolff and Lewis Hamilton in Spain.

While Mercedes is unaffected, Horner has revealed that his team will incur somewhat significant costs to make the change.

“The impact of something like this is probably about half a million dollars,” he revealed.

“That will prevent something else from happening, so that’s the juggling act that we’re now having to make with a budget cap and financial regs.”

Mercedes showed how closely it is flying to the cost cap during the week after pulling out of tyre testing with Pirelli on financial grounds.

Earlier in the year, it experienced a significant unexpected cost when Valtteri Bottas sustained heavy damage to his W12 at the Emilia Romagna Grand Prix

Red Bull and Mercedes have proved closely matched on track, and the former has poached engine staff from Mercedes High Performance Powertrains as its stands up its own engine business.

The rear wing debate could therefore be seen as just another battle ground for the pair to fight over for this year’s world championship.

The Azerbaijan Grand Prix gets underway on Friday, with Free Practice 1 beginning at 18:30 AEST.