Button sets the pace at Barcelona

Button and his BAR-Honda team had not tested since the season-ending Chinese Grand Prix, and had decided to skip the first two days of work at Barcelona.

But the British driver set a blistering pace in his return, setting a fastest time of 1:14.111 to finish well over 1.5 seconds ahead of the closest rival.

Button used two different chassis throughout the day, both fitted with V10 engines, to compare 2004 and 2005 aerodynamic components. Meanwhile, test driver Anthony Davidson worked at the wheel of the hybrid car fitted with the V8 Honda engine, a new gearbox and new rear suspension.

World Champions Renault also got back to work today following their title-winning campaign, with Frenchman Franck Montagny working alongside GP2 racer Jose Maria Lopez. Both men were driving last season's R25 car with restricted V10 engines.

Jarno Trulli and Ricardo Zonta continued with the development of the new Toyota TF106, the duo posting the fastest times of the cars fitted with V8 engines, almost three seconds off Button's pace.

The Italian driver enjoyed a positive day and covered 65 laps, but Zonta was not so lucky and succumbed to problems with the fuel pump twice during the day.

BMW's Nick Heidfeld had a promising session with the C24B car and BMW's new V8 engine, finishing as fifth quickest after 68 laps.

"This was a successful first joint test," said BMW motorsport boss Mario Theissen. "It was important that we could run the BMW P86 engine in the Sauber chassis at this early stage, in order to integrate all technical systems. This is the beginning of the testing season, and there is naturally a lot of work to be done.

"The co-operation at the track as well as the preparation of the interim chassis went very well - it was the first joint task of the new team. This test was the first one of our four that we will be conducting with the interim car before launching the 2006 contender on January 16 and 17."

Scot David Coulthard joined his Red Bull team's preparations, taking over from tester Robert Doornbos and working alongside Austrian Christian Klien, quickest on Tuesday. Both men were at the wheel of the V10-powered RB1 chassis.

Vitantonio Liuzzi was again the only man in charge of testing for the Scuderia Toro Rosso, who made their Formula One test debut on Tuesday with a version of the car raced by Red Bull's other team this year. The Italian was ninth quickest.

Toro Rosso, replacing Minardi on the starting grid, have left open whether they intended to race the RB1 in 2006 - a decision likely to require the agreement of the other teams as well as the world governing body.

The Williams team, working with an hybrid chassis with the new Cosworth V8 engine, finished at the bottom of the times with both Mark Webber and Nico Rosberg, the German driver completing only 18 laps after being hit by mechanical problems early in the day.

The day was filled with red flags by Rosberg, Webber, Lopez, Montagny, Heidfeld and Davidson.

Today's times:

Pos  Driver        Team                Tyres  Time     Laps
 1.  Button        BAR-Honda            (M)  1:14.111   97
 2.  Montagny      Renault              (M)  1:15.848   52
 3.  Trulli        Toyota               (B)  1:17.019   65
 4.  Zonta         Toyota               (B)  1:17.440   20
 5.  Heidfeld      BMW-Sauber           (M)  1:17.559   68
 6.  Coulthard     Red Bull-Cosworth    (M)  1:18.392   38
 7.  Lopez         Renault              (M)  1:18.428   52
 8.  Klien         Red Bull-Cosworth    (M)  1:18.471   89
 9.  Liuzzi        Toro Rosso-Cosworth  (M)  1:19.065   58
10.  Davidson      BAR-Honda            (M)  1:19.231   37
11.  Webber        Williams-Cosworth    (B)  1:19.625   70
12.  Rosberg       Williams-Cosworth    (B)  1:20.444   18

All Timing Unofficial