At a time when speculation continues as to his future, Fernando Alonso has admitted that though Renault is making progress he is unsure whether it is enough, and whether the team can rise from the midfield and battle with the front-runners.

"I am happy with the changes," he told Spain's Diario AS, "but we must continue to improve because others have made progress.

Looking ahead to next week's Spanish Grand Prix, his home race, he added: "It is difficult to say where we are in comparison to them. I will not know until next week."

At present, Renault is sixth in the Constructors' Championship, locked in battle with Williams, Toyota and Red Bull, with Toro Rosso and Honda also showing signs of improvement. This week, in the first test since the season began, the French team has shown signs of improvement, but is it enough?

"We are more or less where we were before the testing," said the two-time world Champion. "We are in the group in which if all goes well you can qualify eighth but if you have trouble then you can be 14th and outside the top 10."

While there is continued speculation regarding a possible move to Ferrari in 2009, a rumour vehemently denied by Renault boss Flavio Briatore, Alonso's failure to talk up his team's chances is hardly likely to endear him to the Maranello outfit, which prefers to keep criticism in-house.