Mercedes is set to lodge a protest against Red Bull at the Formula 1 Azerbaijan Grand Prix as the flexi wing controversy continues.

The rear wing on the RB16B came under intense scrutiny over the Spanish Grand Prix when vision emerged of it appearing to flex under load.

Technical regulations prohibit such a design, with load tests in place to detect teams exploiting such a design principle.

A Technical Directive issued following the Spanish GP advised that those tests would be ramped up following the Azerbaijan Grand Prix.

Furthermore, it added that television footage may be used to determine legality.

A one-month grace period from when the new tests are introduced was announced to allow teams to modify their designs if needed.

That has infuriated a number of teams, most notably Mercedes, with team boss Toto Wolff revealing his squad is ready to protest the Red Bull in Baku.

He argues that, while the wing passes the existing load tests, it still contravenes regulations stating that it should not flex at all.

“I think if the limbo wings are on in Baku, with the advantage that we see, it’s going to go to the stewards, and if the stewards are not enough, then it’s going to go to the ICA [International Court of Appeal],” Wolff told Sky Sports.

“So I guess the FIA is going to clarify things before Baku because if not, it could be very messy.”

Red Bull boss Christian Horner has argued that Mercedes is similarly guilty, alleging the front wing on the W12 deflects in a similar manner.

“We’ve analysed the front wings and they are bending exactly the same way, the Red Bull and the Mercedes wing, so we could be protesting each other,” Wolff countered.

“But it’s clear that the rear wing bends more than it should.

“Under the rules, it has been classified as non-conformant, but we are left in a vacuum where it says a new test will be introduced after Baku.

“We are pretty robust in our legal position.”

The Azerbaijan Grand Prix, the sixth round of the 2021 world championship, takes place on June 4-6.