Christian Horner believes an engine unfreeze needs to be agreed upon because previous regulations were changed to slow down Red Bull.

While Mercedes is guaranteed a constructors' and drivers' title double this year, but for the past four seasons it has been Red Bull which has swept both championships. With the new engine regulations a key part of Mercedes' success, Horner believes the chance for other teams to try and catch up needs to be opened up, hinting that Red Bull was targeted during its dominant years.

"It's very difficult because with the chassis, if you're behind, you have the opportunity to develop," Horner told SpeedWeek. "With the engine and this new technology, you're freezing immature technology and it's very difficult therefore for the manufacturers to recover.

"In the last few years there were regulation changes to try and slow us down, whether that was blown diffusers, double diffusers, flexible body work, engine mapping, the goal posts were always changing, whereas with the engine, it's a frozen untouchable element so it's very difficult to reduce that gap to your opponents."

And Horner went as far as to rank Red Bull's season alongside its title-winning years, such is the gap in performance between the Renault and Mercedes power units.

"I actually think what the team has achieved this year is one of our biggest successes, in that when you consider where we started in the pre-season testing, then to be at this point in the Championship, being the only team other than Mercedes to have won, and to have won three grand prix, to be second in the Constructors' Championship and third in the Drivers' World Championship - it's a remarkable come back from practically no pre-season and obviously the handicap of lack of horsepower that we have compared to the Mercedes-powered cars."