Heidfeld on top at wet Jerez

With intermittent rain showers throughout the day, there was little chance of meaningful dry running - but that did not stop a lot of drivers from completing wet weather programmes.

Heidfeld began the day working on extreme weather tyres before switching to the standard wet tyres for traction control and set-up work. His BMW team, who saw Timo Glock set the third quickest time, packed up at lunchtime though to head to Barcelona for next week's test.

Alexander Wurz ended Williams' encouraging first test with their FW29 with another good showing as he ended the day second overall, half a second behind Heidfeld's best time.

His teammate Nico Rosberg had a less successful day though, finishing sixth overall and bringing out the red flags in the morning after stopping on the way to the garage.

Kimi Raikkonen was fourth quickest for Ferrari, just ahead of Honda's Rubens Barrichello - who stopped on the track at 10:35am with a suspected mechanical problem.

Further down the order, David Coulthard and Mark Webber continued to have their share of troubles with the new RB3.

Tenth fastest Coulthard went off the track at 12:12pm, before returning to action shortly afterwards and then stopping on the track. Webber stopped on track just five minutes later.

The Australian continued to have problems with the seat of his car, although he will get a new one for next week's test at Barcelona.

"I might not want to race tomorrow but I am not really bruised," said Webber of the seat.

McLaren's MP4-22 did not appear to be as dominant in the wet as it was in the dry, with Pedro de la Rosa down in 12th overall on the timesheet.

World champion Fernando Alonso gave up running in the morning, and left the track early.

His decision caught a few Spanish journalists by surprise, and they were seen running down the paddock after his car to try and get some reaction from the Spaniard about how his week had gone.

Marco Andretti completed 62 laps in the Honda and ended the day at the bottom of the timesheets, although less than one second off the pace.

Renault packed up in the morning after deciding that there was little point in testing in the wet, therefore saving some of their tyre allocation.

Today's times:

Pos  Driver        Team                      Time     Laps
 1.  Heidfeld      BMW-Sauber           (B)  1:29.486   35
 2.  Wurz          Williams-Toyota      (B)  1:30.051   69
 3.  Glock         BMW-Sauber           (B)  1:30.213   27
 4.  Raikkonen     Ferrari              (B)  1:30.628   89
 5.  Barrichello   Honda                (B)  1:30.684   64
 6.  Rosberg       Williams-Toyota      (B)  1:30.684   47
 7.  Massa         Ferrari              (B)  1:30.746   44
 8.  Trulli        Toyota               (B)  1:30.981   89
 9.  Montagny      Toyota               (B)  1:31.027   75
10.  Coulthard     Red Bull-Renault     (B)  1:31.166   65
11.  Webber        Red Bull-Renault     (B)  1:31.405   68
12.  de la Rosa    McLaren-Mercedes     (B)  1:31.479   71
13.  Alonso        McLaren-Mercedes     (B)  1:31.573    9
14.  Andretti      Honda                (B)  1:32.387   62
15.  Zonta         Renault              (B)  No time     2
16.  Piquet        Renault              (B)  No time     3

All Timing Unofficial