Run by Fernando Alonso in the afternoon, there were some encouraging signs as the Spaniard ended the day four tenths quicker than Jenson Button in the normal spec car.

Button had said that the best thing that could come out of the weekend would be to see that the upgrades on Alonso's car were much better.

"I think a good weekend would be to see a good improvement with the updates we have, which will hopefully be a good step," he said.

"That is probably the biggest thing really. I don't want to say it is a test weekend. I want to come here and race, I want to come here and compete. We will do all we can to come here and compete."

Big changes

The developments feature changes to the nose, front wing, rear wing, diffuser and turning vanes.

Although McLaren is not calling it a B-spec, the changes are extensive enough for it to have been labelled that if they had wished to.

Here we look in more details about two key areas.

Feeding the diffuser

McLaren MP4-30 Photo by: Giorgio Piola

McLaren made a very sophisticated study on the area in front of the rear tyre, which is a critical area for feeding the diffuser.

In front of the tyre you can see two horizontal longitudinal slots, which other teams have as well.

But what is particularly interesting are the four slots that run down the edge of the floor. This is similar to what Toro Rosso have done, but is much more extreme.

Short nose

McLaren MP4-30 Photo by: Giorgio Piola

The nose appears to be a little bit wider and more square at the section of the new short nose.

If you look at it from the side, the nose is more aggressive than the short nose of the Red Bull which comes down in a smooth S-shape. McLaren drops much straighter.

The assembly of the wing is also totally different – especially the upper flaps are different.