Ahead of today's opening session the air temperature is 30 degrees while the track temperature is 42 degrees.

Other than the fact that this session takes place considerably earlier than qualifying and the race, both of which are held in twilight, thereby making it fairly unrepresentative, team bosses are sure to be spending most of the remainder of the day considering the proposals put forward by Liberty Media earlier as the sport looks ahead to 2021.

Chomping at the bit as he awaits the green light, Verstappen is first out followed by Leclerc, Vettel, Magnussen, Sirotkin and Ocon.

While this session is unrepresentative of the Bahrain weekend as a whole, it makes a great opportunity for testing, hence an abundance of flo-vis.

"Most cars straight out on track with the medium tyre," says Pirelli, "which is here with the soft and supersoft this weekend. This is going to the hottest session, so makes sense to use medium here."

An early issue for Verstappen who on his second lap encounters what he believes is a turbo related issue. The Dutch youngster slows to a crawl before finally parking the car just yards from the pit entrance. Having asked what he can do, the youngster is told to push the car back to the pits... which he does.

Ten minutes into the session and all bar Ricciardo have completed at least one lap, though there are no times on the board.

At which point Ocon stops the clock at 35.687 to get the weekend officially underway. Teammate Perez, who will have exclusive access to a new front wing this weekend, subsequently posts 35.968.

Fifteen minutes in and Ricciardo finally heads out, the Australian subsequently splitting the Panthers with a 35.204, Perez having gone quickest with a 35.191.

Sirotkin is the fourth driver to post a time, the Russian crossing the line at 35.504.

Next time around Ricciardo improves to 34.333 as Stroll goes third with a 35.074.

Purples in all three sectors sees Raikkonen go quickest on his first flying lap, the Finn posting a 33.770.

Quickest only in the final sector, Vettel goes second overall with a 34.318, 0.548s off his teammate's pace.

Meanwhile, Grosjean has gone fourth (34.810) and Vandoorne ninth (35.327), with only 13 drivers having posted times.

A 33.235 sees Bottas go quickest, however the Finn is on the soft whereas the Ferraris and Ricciardo were on mediums. Alonso goes fifth (34.759) on supersoft.

On softs, Vandoorne posts 33.813 to go third, while Grosjean, who is similarly shod, goes fourth with a 33.995.

A spin for Stroll at T8, the Canadian reporting too much oversteer in what is a notorious corner.

Hamilton goes straight to the head of the timesheets on the softs, the world champion posting 33.041.

Moments after Stroll's spin, Leclerc has a similar moment at T7, their cause not helped by a strong tailwind.

A 33.008 sees Bottas re-take the top spot only to be leapfrogged by his teammate once again when he posts a 32.532.

Approaching the forty-minute mark when the extra set of tyres have to be handed back, all bar Verstappen have posted a time.

Despite going quickest in the first and final sectors, Hamilton fails to improve his overall time.

Sainz complains that his car is "an absolute mess... very, very difficult to drive".

At forty minutes, it's: Hamilton, Bottas, Vandoorne, Raikkonen, Vettel, Gasly, Grosjean, Hulkenberg, Ricciardo and Magnussen.

Out come the yellows as a loose bollard is removed. Shortly after Alonso heads out to get things underway again. On the supers the Spaniard posts 33.223 to go third.

Going quickest in S2, Grosjean improves from 11th to 1st with a 32.516... which will go down well with McLaren and Force India. Moments later, teammate Magnussen improves to third with a 32.971.

A rare mistake from Hamilton who locks-up and runs wide in T10. The Briton subsequently reports his tyres as being "dead".

No such issues for Bottas who goes quickest in the two final sectors, crossing the line at 31.364, 0.908s quicker than his teammate's best.

Meanwhile, Gasly goes fourth (32.779) and Sainz fifth (32.885) as they switch to the supersofts.

"Box, I have a problem," warns Leclerc. "Steering wheel is not straight at all."

On softs, Raikkonen posts PBs in all three sectors, going second to countryman Bottas by 0.094. Impressive.

Vettel heads out, the German also on the softs. The German goes quickest in S1, though in S2 he can only manage a PB. At the line it's 31.470 which puts him third, 0.106s down on Bottas.

Sirotkin reports a problem with changeable wind.

With 16 minutes remaining, Verstappen has still to post a time, while Ricciardo is 18th having only completed 10 laps. Also in the nether regions of the timesheets are Ocon, Perez, Ericsson, Hartley and the Williams duo.

That said, Ricciardo is back on track, on softs, and he's about to make a significant improvement. Indeed, going quickest in the final two sectors he crosses the line at 31.060 to go quickest.

Alonso, currently 11th, is told to pit for a change of nose box.

Attention now focusses for most on long run pace.

Back on track, Hamilton, 1.2s down on pace-setter Ricciardo, really appears to be struggling, the Briton running wide for the second time this afternoon.

As one might expect, Haas is making full use of the opportunity for some live pit stop practice.

Having complained about a slow McLaren (Alonso), Leclerc subsequently has a moment involving Grosjean leaving the Frenchman far from impressed.

The session ends but each team is allowed to send out one car for a practice re-start behind the safety car.

Ricciardo is quickest, ahead of Bottas, Raikkonen, Vettel, Hamilton, Grosjean, Gasly, Sainz, Magnussen and Hulkenberg.

Alonso is eleventh, ahead of Leclerc, Vandoorne, Stroll, Sirotkin, Hartley, Ericsson, Perez, Ocon and Verstappen.

Check out our Friday gallery from Bahrain, here.