Red Bull have significant upgrade package for Spain

Red Bull is unveiling a significant upgrade package for the Spanish Grand Prix, reportedly centred around a radically-short nose for the RB11 car.

And Renault is also pushing on, announcing a "modified spec" of its troubled turbo V6 for the weekend in Barcelona.

Horner said: "We want to try and make a good step forward over the coming races and try and put Williams, and maybe even Ferrari, under a bit of pressure."

But for mer Red Bull driver Mark Webber believes the real sights have already been turned to 2016.

"Red Bull want to be fighting for a world championship next year," he said. "If there's any positives about having a brutal season, it's that you can cut your losses and focus on next year's car."