Mercedes and Ferrari 'working as one team', says Red Bull's Christian Horner

Ladies and gentlemen, your 2018 F1 cars (1:38)

With day one of testing begun, here's a recap of what the news cars look like for the upcoming season. (1:38)

MONTMELO, Spain -- Red Bull boss Christian Horner believes Mercedes and Ferrari are working together to shape Formula One's landscape in their favour.

The start of 2018 pre-season testing has reignited focus on the political battles expected to dominate this year, as F1 owners Liberty Media continue to negotiate with teams about the post-2021 engine regulations. Ferrari threatened to quit when the original proposal was tabled in the latter stages of 2017 and has recently floated the idea of creating a breakaway series. Mercedes was also apprehensive about Liberty's blueprint.

Horner used his first official media appearance of the test to take a dig at the pair, who fought for last year's championship, while also poking fun at Mercedes' decision to broadcast Ferrari's Maranello launch shortly after its own at Silverstone last week.

"Mercedes and Ferrari are working as one team these days," Horner told Sky Sports. "Sometimes it is difficult to tell which is which. For the last couple of years there has been a very tight relationship between Ferrari and Mercedes. They even broadcast each other's launches and things like that these days."

In his print media session which followed the Sky interview, Horner echoed McLaren boss Zak Brown's opinion Liberty must have a concrete engine proposal in place by mid-way through this season.

When asked what would be on the top of his wish-list for 2018, Horner said: "I think to come out with a clear set of engine regulations for 2021. That's the longest lead-time item.

"That's the element that needs dealing with the quickest, the rest you can deal with as you go along. I think it's so fundamental to what Formula One currently is in terms of performance, cost, noise, entertainment. I think it's an absolute fundamental that needs to be addressed."

Referring to the strength of Mercedes and Ferrari's negotiating positions, Horner then went on to point out it does not matter what any team believes if Liberty and the FIA are on the same page.

"It really needs alignment between the commercial rights holder and the governing body. As soon as they are on the same page it becomes irrelevant what the teams want. First things first, they need to align themselves and then present what they want the regulations to be, particularly as far as the power units are concerned. We've got interested parties sitting outside Formula One and again, timing is crucial for them if they are looking at entering F1 in 2021.

"Liberty had a positive first year, they did a lot of good things around the sport. But a lot of that is window-dressing, it's not dealing with the fundamentals of the product. The next 12 months is going to be a crucial 12 months for the FIA and for Liberty, where they've got to get on the same page and then present what they want to do and what they see Formula One as from 2021 moving forward. That is so important to the entrants to know what they're signing up for."