Sebastian Vettel headed the timesheets on the first day of testing at Barcelona, the German finishing ahead of Nico Hulkenberg and Lewis Hamilton.

Vettel, who completed 79 laps, lost time in the early afternoon while the team made changes to his car. Like most of his rivals he set his best time of the day during the morning session.

"It's clear that the cars have less grip than last year," said the world champion, "but we try to come back from that slowly. It's difficult to judge where we are compared with the others right now. It's all based on feeling and the feeling I have inside the car at the moment is fine. I think we had a good day today, with no trouble. We had a long lunch break when we made some changes, but not because anything broke down. All in all, it was a good day."

"We got through most of what we wanted today," said Ian Morgan, head of race engineering. "We had a longer than usual break for lunch, in order to change some things, but that had always been planned. So, while we lost a little time, it wasn't at the expense of getting the tasks completed.

"These tests are a process of continuous development," he continued, "and the programme today was influenced a bit by what we learned at the last test. We also had to test some items that were put into development before the car even took to the track.

"The next two days will be somewhat different," he added. "We will be doing race simulations and will have the whole race team here, so we will try to mix that with continuing the development. There aren't many chances to run through a whole race weekend before the season starts and we'll do a simulation with each driver. Those should keep us on our toes for the next couple of days."

Second quickest was Nico Hulkenberg, whose programme included tyre comparison work, aero sweeps and long runs in the afternoon.

"Once gain it's good to do so many laps," said the German, "and I'm pleased with how things went today. It was only my second day in the car and I'm still bedding in and getting used to things, but after each run I felt a bit more comfortable. We started with some aero runs and more data gathering this morning, and then moved to longer runs in the afternoon. The car feels consistent and the drivability is good so I feel positive heading into tomorrow."

"Another busy day with a lot of mileage for Nico as he continues to build up his feel for the VJM05," added chief engineer, Jakob Andreason. "We began the programme with aero sweeps and also evaluated some mechanical components to address some improvements we felt could be made to the car following the Jerez test. The car has performed well throughout the day with good reliability, which allowed us to focus on adding performance. We completed the majority of the programme and got through our long runs in the afternoon, which helped build up Nico's knowledge of the hard and medium compound tyres."

Second busiest driver today was Lewis Hamilton, the Englishman completing 114 laps on his way to posting the third best time of the day. His day began with some initial data collection, including aero work on newer rubber before his engineers began a more comprehensive programme of tyre and set-up evaluation for the remainder of the morning.

After completing a number of shorter runs, focus in the afternoon turned to longer runs, with the McLaren driver declaring himself pleased with the MP4-27's behaviour, particularly in the high-speed corners.

"With more than 500kms under our belt, this was an extremely productive day," said team manager, David Redding. "The car ran reliably and without problem all day and Lewis was happy with the car. Given the cooler temperatures we experienced today, we're optimistic that we're headed in the right direction with our tyre and set-up work for the start of the season."

It was another positive day for Toro Rosso, who had Daniel Ricciardo on duty as the team worked on evaluating several set-up configurations with various fuel loads.

Unfortunately, the day was cut short with a technical problem that stopped the car out on track and with only one hour of the day remaining, there was not enough time to get the car back on the circuit.

"It was a good day with 76 laps under my belt," said Ricciardo. "In the morning, apart from working on the overall development of the car, we were also getting ready for Melbourne, running through various procedures, working to a set time scale, as if it was a race weekend. That went well and in the afternoon, we did some race-type runs which were successful until the car stopped with just the final hour to go."