Button sets early pace

Formula One's return to Europe sees the cars sporting revised aero packages as the teams either attempt to keep their noses in front, or claw back the deficit after the opening flyaway races.

As indicators go, Button's hot lap on soft tyres in the dying embers of the opening 90-minute practice session for Sunday's Spanish Grand Prix that put him on top of the timesheets could prove to be a significant one.

The World Championship leader is the man to be shot at given his and Brawn GP's stunning start to the year, and he is the favourite for the crown at this stage.

The 29-year-old certainly set the pace at the Circuit de Catalunya by posting a time of one minute 21.799 seconds that was more than a third of a second quicker than his nearest rival.

That was Toyota's Jarno Trulli, the polesitter at the Bahrain Grand Prix 12 days ago, followed by the BMW Saubers of Robert Kubica and Nick Heidfeld.

The duo had previously spent most of the session languishing in the bottom five in a car that for this race does not house the new double diffuser as the German marque felt it offered little improvement on performance to their upgraded aero package.

The Williams pair of Kazuki Nakajima and Nico Rosberg were fifth and sixth, with Renault's Nelson Piquet seventh and the second Toyota of Timo Glock in eighth.

The Ferraris of Felipe Massa and Kimi Raikkonen, both desperately hoping to rediscover some sort of form following the worst start to a season in the team's history, were ninth and 11th, sandwiching Rubens Barrichello in his Brawn.

The so far strong Red Bulls were surprisingly off the pace, with Mark Webber and Sebastian Vettel 12th and 13th, with McLaren's Lewis Hamilton down in 14th.