Red Bull 'right on the limit' for 2016 F1 season, Horner admits

With four weeks of the season remaining, and with the first 2016 pre-season test just 112 days away, the clock is ticking for Red Bull on its future in F1.

After deciding to split from power-unit supplier Renault at the end of the season, talks have so far foundered with Mercedes and Ferrari, and while , McLaren Group CEO .

Discussions remain ongoing with McLaren and Honda, while Autosport understands a reunion with Renault is not beyond the realms of possibility as the French manufacturer has yet to confirm a split from its standpoint.

But Red Bull team principal Horner concedes something has to be resolved soon for the marque to appear at Barcelona's Circuit de Catalunya on February 22.

"At the moment we're right on the limit to be at the first test," declared Horner.

"But the team in Milton Keynes have demonstrated their ability to work to massively tight deadlines.

"I'm sure we will be able to meet whatever targets we need to, as long as we come to a decision [on engine supplier] in the next couple of weeks."

Why Red Bull's tactics have failed

Asked by Autosport as to when Red Bull hits the point of no return, Horner replied: "Melbourne next year!

"We're working hard to find a solution, and behind the scenes there is an awful lot going on to achieve that.

"Obviously certain obstacles are being placed in our way, but when the time is right, we'll sit down with all of you guys [the media] and tell you very clearly what we're doing."

Horner, meanwhile, is convinced that the uncertainty over Red Bull's future will not lead to an exodus of worried staff.

As to whether personnel would likely be poached, Horner said: "No, I'm confident all the key members of staff know what the situation is.

"Working for Red Bull is different from working for other teams - when we do something, we do it properly.

"We want to get ourselves into a position where we can compete, and race, and have a bright future."

Horner has confirmed Red Bull will be taking part in the one-day Pirelli tyre test on December 1 in Abu Dhabi, two days after the grand prix.

As to its presence at the wet Pirelli tyre test at the Paul Ricard circuit on January 25-26, Horner said: "Obviously that is slightly more of an issue."