Gary Paffett topped the timesheets on the first day of testing, as preparations for the 2006 got underway at Barcelona.

Following the post-season break, today's session marked the first day of an intensive three week programme in the build-up to Christmas.

Test driver Alex Wurz was joined by Paffett, who was testing with the team having been crowned 2005 DTM Champion. Both drivers were at the wheel of interim MP4-20Bs, which were running the new Mercedes-Benz V8 engine, the FO108S.

Wurz was the second fastest driver of the day, though his running was affected initially by transmission problems, further compounded by hydraulics systems issues, which were resolved by the test team during the course of the day.

"I'm really happy to drive a Formula One car again after more than two years," said Paffett. "I gained a lot of experience and enjoyed driving very much. For me, cornering speeds and braking were most impressive. However, the difference between the DTM and the Formula One car is not as big as it was between the Formula 3 and the Formula One car three years ago. Co-operating with the technicians I benefited a lot from my experience in the DTM. I'm already looking forward to continue testing tomorrow."

"It was great to be back in action today," added Wurz, "however my running was limited because of minor issues with the car, which have now been resolved. I am looking forward to be back behind the wheel tomorrow to really experience the V8 and being able to put in more laps."

"After an almost three-month break I could hardly wait for the first test," said Nick Heidfeld, who suffered a technical failure in the late afternoon.

"The chassis and engine ran without any problems in the morning," he admitted. "All the systems were working perfectly. Of course you can tell the difference in performance compared to the V10. That's something you just have to get used to. A positive surprise is that the engine vibrates a lot less than I had expected. In the afternoon we had to break off work early when the engineers spotted a problem in the data and told me to switch off the engine."

On Tuesday, Williams-Cosworth, Red Bull-Ferrari, Toyota and Toro Rosso, join in the fun.