Formula 1 testing: Red Bull unhappy with Mercedes upgrade in Bahrain

Mercedes are at the centre of a row over the legality of their car after introducing a radical new design at the second pre-season test.

Formula 1 managing director Ross Brawn said the car's aerodynamics around its sidepods was a «very extreme interpretation of the regulations».

Red Bull team boss Christian Horner told Germany's Auto Motor Und Sport: «Mercedes have gone a step too far.

»That does not correspond to the spirit of the regulations," he said.

«For us, these wings are illegal.»

Red Bull initially described the quotes attributed to Horner as «incorrect», before clarifying they were not «official».

Horner later told Sky Sports: «I was slightly surprised to be reading comments that I was supposed to have been making.

»I haven't paid a great deal of attention to [the Mercedes car]. It is obviously a fairly different concept, but that is for the aero guys and the designers to get into."

The revised Mercedes has been dubbed the «no sidepod car» because of the extreme way the world champions have managed to shrink the bodywork beside the driver around the car's cooling requirements.

Horner also seems to have taken issue with the integration of a shaped side-impact structure on which the rear-view mirrors are mounted.

He said: «Those are not mirror mounts, but two wings. In addition, they have built vertical baffles on top. They have nothing to do with the mirror mount.»

Ferrari team principal Mattia Binotto also raised questions about the Mercedes design.

«No doubt it is a great car — that should not be a surprise to us,» he said. «A concept quite different to ours, quite interesting with the cooling layout, and the sidepods.

»On the mirrors, it was surprising — we were not expecting that. We always said the mirror should have