Button’s fastest lap was 1:21.140, more than half a second faster than Toyota’s Jarno Trulli, whose time was 1:21.85s.
Testing times are not a reliable indicator of overall competitiveness, but reliability can be judged to an extent. The new Brawn car, which had its shakedown at Silverstone last week, completed 30 trouble-free laps at the Circuit de Catalunya this morning.