On his first day back at work, following the Christmas and New Year break, Jenson Button topped the timesheets, as testing continued at Jerez.

The Englishman, who was partnered by Anthony Davidson, posted a best time 0.25s quicker than the next quickest driver, Jarno Trulli.

With Honda's 2006 car not due to make its track debut until next Wednesday (25), both drivers were at the wheel of 'concept' 2005 cars, albeit fitted with the 2.4 litre V8 powerplant.

Button ran through tyre and aerodynamic evaluations, however, he lost track-time as a result of two (unspecified) failures which caused him to stop out on track.

In the morning, Davidson completed a couple of set-up runs followed by an aero evaluation. In the afternoon, he ran through a tyre evaluation and further aero work.

Between them, the two Brackley drivers covered 229 laps, with Davidson completing 133.

Splitting the two Hondas was another Japanese car, the Toyota TF106 of Jarno Trulli, who was joined by Ralf Schumacher.

Unfortunately both drivers had disrupted days and could not put in as many laps as they would have hoped, but the team still gained useful experience of the TF106.

Ralf put in some solid work on suspension settings but a gearshift problem limited his running time in the afternoon. Jarno missed some of the morning session after a clutch sensor problem but he carried out a tyre test in the afternoon and posted the 2nd quickest time of the day. The two drivers will be back at the track tomorrow for the final day of this week's test.

Yesterday's pace-setter, Pedro de la Rosa, could 'only' manage fourth fastest today, finishing 0.836s down on Button. The Spaniard was joined by Gary Paffett, as the two McLaren drivers concentrated on Michelin development work.

As with yesterday, the cold weather conditions at the Spanish circuit saw a delay in the start of running, which got underway properly at around 10am. Paffett ventured out on track slightly earlier, and as a result of the cold conditions had a small off, but the car was undamaged.

McLaren will resume its pre-season test programme next Monday (23rd) at the Circuit de Catalunya with Pedro and Gary continuing driving duties.

"Over the past two days in Jerez, we have again completed some positive work with Michelin on tyres, alongside set-up and some weight distribution programmes," said de la Rosa. "There was cold weather both mornings, which delayed the running slightly, but we were still able to complete some good mileage."

"We had another productive session this week in Jerez," added Paffett. "I am continuing to settle in well with the team and am looking forward to carrying on the programme next week in Barcelona."

Nico Rosberg was joined by Alexander Wurz as the Grove outfit continued with its programme. The former McLaren test driver was the quicker the two, despite suffering a technical failure which sidelined him in the afternoon.

Weather
Air temperature: 16 C
Track temperature: 23 C.
Cold in the morning, sunny in the afternoon