British F1 driver Paul di Resta believes his Force India team have developed significantly since his arrival at the team one year ago. The latest challenger from the Silverstone-based team, the VJM05, appeared to be one of the most impressive on track yesterday as testing began in earnest.

Di Resta completed 101 laps of the Jerez track in southern Spain, finishing marginally behind the pace-setting Lotus of the returning Kimi Raikkonen. The Scot, who last year enjoyed a fine second half of the season to guarantee his seat for this campaign, certainly gave off an air of contentment.

"We got through all our programme, and a bit more, because we had a good approach," said Di Resta. "It was all fairly good and we can be relatively happy with the work we've done over the winter and what the guys have achieved. "All the fancy engine modes have gone, as have the exhausts, and we've lost a ton of downforce, but the car is well balanced.

"That gives you encouragement that what has gone on in the background, with simulations and stuff, is working well. "If we look where we were a year ago compared to where we are now, it is a massive step up the road. It's almost three seconds. "All I can say is it was a very productive day. We can be happy with what we've done. It's a good starting point to work away."

Di Resta underlined, however, the smoke and mirrors nature of what can unfold during a test, as occurred a year ago in Jerez. "We achieved 101 laps on the first day out, which means mileage and reliability were good, which is always a positive," Di Resta told Press Association Sport. "Now, all this test is about is gathering information. It's not about performance.

"Somebody asked me earlier 'Who was fastest at this test last year?' and I didn't know, and then they told me it was Rubens (Barrichello, then with Williams). "I couldn't tell you who was then fastest in the Barcelona test last year, but I could tell you who was on pole at the first race. "That's all this test is fundamentally about, correlating what is happening back at the factory to ensure the next upgrade we bring before Melbourne works.

"So you just need to make sure the car is the same as the information you are getting from the wind tunnel." One bonus for Di Resta this week is that he has cousins and fellow professional racers Dario and Marino Franchitti to keep him company. Di Resta added: "They came down and did some training with me before Jerez, and then they came here with me. They were actually at this test last year. "It's good for them to come down and see what is happening in Formula One because it correlates over to what they're up to. "If the time is there I always go and see them. It's nice to have them about, and it's nice to have the support."