The first free practice session on Friday for the Spanish Grand Prix started in wet weather, meaning that teams were forced to concentrate their running in the final moments of FP1 and a dry FP2. At the end of FP2, Red Bull’s Sebastian Vettel topped the time sheets with a lap of 1:22.808s on the Pirelli P Zero White medium tyre, which has been nominated along with the P Zero Orange hard for Barcelona. This was significantly quicker than last year's equivalent FP2 time (1:23.399s) set on the soft tyre.

A new version of the P Zero Orange hard tyre was introduced this weekend with a wider working temperature window. In addition, teams were also able to benefit from an extra set of experimental hard tyres per car for Friday only - as Pirelli is allowed to supply in accordance with the regulations.

The drivers ran mostly on the Cinturato Green intermediate tyres in the morning, using the experimental hard tyres in the final 15 minutes of the session, with the Ferrari duo of Fernando Alonso and Felipe Massa going first and second fastest. The cars continued to run on both the experimental and nominated hard tyres during FP2. Toro Rosso's Jean-Eric Vergne was the first driver to switch to the mediums half an hour into the second session, as the teams concentrated on race simulations in order to establish an optimal tyre strategy.

Paul Hembery: The first race of the European season is always a significant one, with most of the teams introducing key upgrades. At Pirelli, we're no exception, with the latest version of our hard tyres coming to Spain together with two sets of an experimental compound per team. Despite the rain in the morning, we saw plenty of running as the teams worked through their development programmes during both sessions, which was our objective. The rain meant that we don't have a full set of dry data to analyse this evening, but the initial feedback from the drivers about the new hard tyre - which has a wider working temperature window - is extremely positive. There is still a lot of track evolution to come: so far we are seeing a difference of just under a second between the two compounds and high wear, which is to be expected on an aggressive track like Barcelona, but we would expect that to come down a bit over the rest of the weekend, which has a consequent effect on degradation. We'll be able to make a more accurate prediction after the final free practice session and qualifying tomorrow. Obviously there was a problem in the final part of FP2 that affected the medium tyre on the Force India of Paul di Resta and we're going to investigate the cause of that fully. Whatever the cause, this is not something we like to see and once we have established all the facts we will decide whether some further modifications to the tyres are required to help avoid this type of issue.

Check out our Friday gallery, here.