Ahead of today's opening session the air temperature is 21 degrees C, whilst the track temperature is 25 degrees. Though it is somewhat bright, the track remains damp following earlier showers, meaning we could see some initial running on Inters. Furthermore there is a 20% chance of further rain.

There are a couple of big stories today, the first being that Nico Rosberg has agreed a new two-year deal with Mercedes, though this has yet to be officially confirmed.

The other big story is that as the FIA continues its crackdown on all things naughty (or entertaining), the kerbs at Turns 4 and 11 have been fitted with "installed loops 1.6m from the track edge which will alert officials when a car has all four wheels off the track."

Naturally, the drivers have mixed opinions about this, just as they do over the crack down on radio communications.

The 'bugged' kerbs are among a number of changes at the circuit which has been completely resurfaced.

Once again the tyre options are medium, soft and supersoft, whilst the DRS activation zones are after the apex of Turn 14 and after the apex of Turn One.

There are two reserve drivers on duty, Esteban Ocon at Renault (replacing Magnussen), and Charles Leclerc at Haas replacing Gutierrez.

The lights go green and Wehrlein leads the way, followed by Vettel, Bottas, Raikkonen and Ocon. All are on Inters.

Soon all but Hamilton have been out to test the waters, most heading back to the pits after a single exploratory lap.

Ricciardo's car is fitted with sensors, Red Bull using this as a test session.

Indeed, the Austrian outfit is seen as a major threat to Mercedes this weekend.

Grosjean reports that T3 and T9 are "quite damp".

Having completed an installation lap, Hamilton heads out again along with his teammate.

With little prospect of rain for the remainder of the weekend there is little to be gained from running in the damp on Inters, consequently it is almost twenty-five minutes before we see the first time of the day... Bottas posting 1:28.748 on a set of softs.

Moments later Alonso, also on softs, posts 27.876.

Rosberg (softs) posts 27.966, Raikkonen (supers) 26.132 and Hamilton (softs) 26.106 as we finally get some action.

Leclerc is one of several drivers to run wide in T11.

A 24.088 sees Rosberg go quickest, ahead of Raikkonen and Vettel.

Just over thirty minutes in and all but Leclerc and Nasr have posted times.

Hamilton raises the bar with a 23.885 as Ricciardo runs wide in T5.

"That's quicker than any Friday time from 2015," reports Mercedes of Hamilton's lap, "and he's not even on the SuperSoft."

Vettel has a big moment as he runs over a damp kerb - that will have set off alarm bells, if only in his underpants.

A big lock-up for Button, who asks his team to help identify what caused it.

"Little niggle" on Palmer's car according to Renault.

After forty minutes, when a set of tyres has to be handed back to Pirelli, the order is: Rosberg, Hamilton, Ricciardo, Verstappen, Button, Vettel, Raikkonen, Hulkenberg, Alonso and Perez.

Taking advantage of the lull, Ocon posts 25.260 to go 11th.

Now on the supersofts the Mercedes stamp their authority on the opposition, Rosberg posts 21.584 and Hamilton 21.347, Ricciardo, on softs, remains 2.5s off the pace in third.

A spin for Alonso in the final corner as the Spaniard loses the rear of the car.

Wehrlein reports something strange with his car, the German currently 18th,

As Vettel spins at T12, Hulkenberg goes fifth with a 24.120 only to be demoted when Grosjean posts 24.013.

The Frenchman, like the Mercedes duo, is on the red-banded supersofts, the rest of the top ten currently on softs.

Check out our Friday gallery, here.