Spain P2: Button takes control

Jenson Button overcame balance problems on his revised MP4-27 to set the Practice 2 pace in Spain for McLaren.

In the early stages of the afternoon session the 2009 World Champion was twice heard over his team radio complaining about chronic understeer - Button on the second occasion labelling the handling imbalance "unbelievable", despite attempts by the team to dial it out during his previous visit to the pit lane.

However, a switch to the soft compound tyres appeared to do the trick all on its own as Button suddenly uncorked a lap of 1:23.399s to leap ahead of Sebastian Vettel and Lewis Hamilton and move to the top of the timesheet.

Vettel had earlier used his first lap on the 'option' compound for this weekend to lap in 1:23.563, the second McLaren of Hamilton having been unable to get within 0.3s of the Red Bull despite two hot laps on the same tyre. The Briton later twice went off the road in the final complex during his race simulations, with numerous drivers finding the conditions tricky.

Mercedes spent the early part of the session clearly concentrating on heavier fuel runs on the harder tyre - their drivers circulating towards the bottom of the timesheet as a result. Eventually, though, Nico Rosberg worked his way up the order to third ahead of Hamilton to suggest the Brackley squad may again be a threat this weekend.

The team many pundits are tipping for victory, however, are Lotus and they plotted a similar course early on in the afternoon to Mercedes, with their drivers continuing to assess the new front wing the team have brought this weekend.

However, Kimi Raikkonen and Romain Grosjean eventually set the fifth and sixth fastest times respectively before both ominously started reeling off some consistently strong times on their respective end-of-session race simulations.

Mark Webber took seventh in the second Red Bull, the Australian taking a trip through the gravel at turn four mid-way through the session, with six-time Barcelona winner Michael Schumacher in eighth.

Meanwhile, any encouragement Ferrari fans may have drawn from Fernando Alono's pacesetting morning form may have diminished somewhat heading into qualifying after both of their cars finished outside the top 10 in the faster second session.

While Felipe Massa all but matched his Practice 1 performance, crowd favourite Alonso slipped to 14th - although the fact the Spaniard actually lapped just over a tenth slower on the soft compound than he managed on the hards in the morning suggests he was running with heavier fuel.

Nonetheless, given many were expecting the Maranello marque to make a big step forward here, the team still have a lot of questions to answer over the F2012's ultimate potential for the remainder of the weekend.

At the foot of the order, HRT's Narain Karthikeyan completed just two laps after an apparent reoccurrence of the electrical problem that had earlier sidelined test driver Dani Clos in the same car.