Button fastest in final practice - Bahrain

The British Honda driver set a time of 1:31.857 to edge out his nearest rival by 0.011 seconds.

Germany's Michael Schumacher was second fastest in a Ferrari ahead of the Renaults of world Champion Spaniard Fernando Alonso and Italian Giancarlo Fisichella.

Schumacher's Brazilian Ferrari teammate Felipe Massa was fifth fastest but went off the track at turn eight in the final minute of the session to end his hopes of stealing the top spot.

A minor sandstorm at the circuit early in the morning left the 5.4 kilometre circuit coated in a layer of fine sand, and with meaningful running impossible in the conditions, none of the big teams sent their drivers out until one third of the session had passed.

Button was the first front-runner to send to set a competitive mark after lapping in the high one minute 37 bracket on his first flying lap, and the times kept tumbling from then on as the track developed more grip.

Toyota were off the pace for much of the session, suggesting that German Ralf Schumacher, who was ninth, and Italian Jarno Trulli, who set one quick lap to lie seventh, will run heavier fuel loads than most in official qualifying later today.

And the McLarens of Finn Kimi Raikkonen and Colombian Juan Pablo Montoya were even slower in ninth and 15th, although both were running on old tyres.

Midland F1's Dutch driver Christijan Albers gave the crowd some entertainment with a spin when he hit a kerb midway through turn one.

Japan's Yuji Ide was the only driver to complete a flying lap during the first 20 minutes of the session as he continued to learn both the track and the Super Aguri SA05

But he suffered a driveshaft problem and pulled off the track at the pit exit after half an hour.

Pos  Driver        Team                     Time                  Laps
 1.  Button        Honda               (M)  1:31.857               16
 2.  M.Schumacher  Ferrari             (B)  1:31.868  +    0.011    8
 3.  Alonso        Renault             (M)  1:31.975  +    0.118   11
 4.  Fisichella    Renault             (M)  1:32.050  +    0.193   12
 5.  Massa         Ferrari             (B)  1:32.826  +    0.969    6
 6.  Villeneuve    BMW-Sauber          (M)  1:32.913  +    1.056   14
 7.  R.Schumacher  Toyota              (B)  1:33.038  +    1.181   16
 8.  Raikkonen     McLaren-Mercedes    (M)  1:33.262  +    1.405   12
 9.  Trulli        Toyota              (B)  1:33.523  +    1.666   14
10.  Webber        Williams-Cosworth   (B)  1:33.876  +    2.019   11
11.  Klien         Red Bull-Ferrari    (M)  1:33.944  +    2.087   14
12.  Barrichello   Honda               (M)  1:34.009  +    2.152   15
13.  Heidfeld      BMW-Sauber          (M)  1:34.094  +    2.237   11
14.  Coulthard     Red Bull-Ferrari    (M)  1:34.142  +    2.285   16
15.  Montoya       McLaren-Mercedes    (M)  1:34.406  +    2.549   11
16.  Rosberg       Williams-Cosworth   (B)  1:34.434  +    2.577   11
17.  Albers        MF1-Toyota          (B)  1:34.541  +    2.684   14
18.  Monteiro      MF1-Toyota          (B)  1:35.026  +    3.169   14
19.  Liuzzi        Toro Rosso-Cosworth (M)  1:35.351  +    3.494   13
20.  Speed         Toro Rosso-Cosworth (M)  1:35.532  +    3.675   13
21.  Sato          Super Aguri-Honda   (B)  1:36.994  +    5.137   15
22.  Ide           Super Aguri-Honda   (B)  1:41.889  +   10.032   10

All timing unofficial