Days ahead of the start of pre-season testing, Red Bull boss Christian Horner has admitted that the team's 2015 contender isn't fully finished.

With two days before McLaren becomes the first team to officially launch its 2015 car - rather than renderings - and just five days before testing gets underway, Horner has revealed that work on the Austrian outfit's car continues.

Asked, at a 'meet the drivers' event at an indoor skiing facility in Milton Keynes, whether the RB11 was ready, Horner admitted: "Not yet, no.

“We are flat-out into car build at the moment," he continued, "this is probably the shortest production and assembly time in our ten seasons, it is unbelievable what the factory have turned around so far. So there is still plenty to do before Sunday.”

Memories of last year's test at Jerez still haunt the Austrian team, having completed just 21 laps over the course of the four days.

"Hopefully this one can't be any worse than that," smiled Horner. "Hopefully we've made progress. I think it's been a far more positive winter compared to last year. We know where the benchmark is and what we need to achieve.

"Last year was tough but we still finished second in the Constructors' Championship, third in the drivers' with Daniel, and won three grands prix," he added. "I would say it was a year of evolution, particularly with this new power unit. But the whole team has been working incredibly hard over the winter and we're hoping to close that gap down to Mercedes. They'll be the benchmark again but hopefully we can give them a hard time. They had a significant advantage at the end of last year. Hopefully we will have made significant inroads into that advantage. Renault is taking an aggressive development approach to this year."

One of the biggest changes in terms of the RB11, is that Sebastian Vettel won't be driving it, the four-time champion having upped sticks to Maranello. Consequently, Ricciardo is joined by Daniil Kvyat, the Austrian team taking a massive gamble by promoting the Russian after just one season.

"They're both very quick they're both products of the Junior Team, so there's a really exciting dynamic within the team. It's a real evolution for the team to have two such young, promising drivers. They know what's expected of them and it's our job to support them and get the best out of them."

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