Ahead of today's opening practice session the air temperature is 17.4 degrees C, while the track temperature is 23.2 degrees. There has been overnight rain, and the chance of further rain during this session is 20%. Indeed, in the moments before the lights go green, it begins to drizzle.

While we await the latest instalment in the Mercedes/Red Bull battle, attention will be firmly fixed on Ferrari and how it recovers from its dreadful start to the season.

Also of interest will be McLaren's progress and the see-saw form of Racing Point, whose cars are currently being investigated by the FIA.

Norris is first out, followed by Ricciardo, Kubica, Ocon and Vettel. All are on hards.

As Russell heads out on softs, Leclerc, Kvyat and Sainz are sporting mediums.

A number of cars, not least Ricciardo's Renault, are sporting a large array of sensors.

Six minutes in and all bar Gasly, Verstappen and the Mercedes pair have appeared.

At which point Verstappen heads out... on hards.

The Dutchman gets straight down to work, posting the first time of the weekend, a 1:19.536.

Norris reports that it is "spitting a little bit", as Verstappen improves to 19.440.

Fifteen minutes in, Bottas is the first of the Mercedes pair to head out, the world championship leader already on softs.

"We've got a lot of surge," reports Verstappen after a number of lock-ups, "we'll have to look into that." He subsequently posts an 18.383.

A 17.765 sees Bottas go top with his first flying lap, as teammate Hamilton finally heads down the pitlane.

The Briton, also on softs, subsequently posts 17.438 to go second, Bottas having improved to 16.559.

Magnussen goes fourth (20.861), ahead of Albon, Kvyat and Norris.

A 19.493 sees Sainz go fourth on the mediums.

As Vettel posts 19.032 to go fourth, Bottas raises the bar by 0.005s to 16.544.

Stroll goes fourth with an 18.911 as teammate Perez goes seventh (18.952).

Leclerc posts 18.803 to go fourth, the Ferrari driver crossing the line at 18.803.

Moments later however he is demoted when Ricciardo posts 18.706.

Though the times are way off the pace of the Mercedes pair, don't forget that the Black Arrows are on softs.

A brief spin for Kubica in T1 brings out the yellows. "It's all OK," reports the Pole who is on hards.

Magnussen improves to sixth on the hard, the Dane stopping the clock at 18.827.

However, in moments he is demoted as Russell and Albon both go quicker.

After thirty minutes the only driver yet to appear is Gasly, though it is unclear why.

Having moved away, Norris reports that the drizzle has returned as Ocon becomes the first driver to have a lap time deleted after exceeding the track limits at T12.

Perez (hards) improves to third with an 18.085 as Verstappen argues that he's learning nothing and it's raining and he wants to pit. Which he duly does.

Wow! An 18.175 sees Latifi go fourth, albeit on the softs.

A lock-up for Hamilton in T1 sees the world champion run wide.

AlphaTauri confirms that Gasly's non-appearance is due to an engine issue, which Honda describes as an "anomaly".

Though the rain is only light, of the opinion that it doesn't represent the conditions for the remainder of the weekend, the drivers head to the pits en masse, conveniently this coincides with the point at which they hand their first set of tyres back.

Hamilton is quickest, ahead of Bottas, Perez, Stroll, Latifi, Leclerc, Verstappen, Vettel, Ocon and Sainz.

Following a brief lull Grosjean breaks the deadlock, the sound of the Ferrari filling the air. He is sporting mediums.

Bottas, Norris and Magnussen are next out.

An 18.071 sees Magnussen go third, albeit 1.982s off Hamilton's pace. However, he is demoted when Perez posts 16.661 on the softs.

Hamilton heads out on mediums and Bottas hards.

The timing screen lights up as drivers eye the dark clouds moving in.

Stroll goes fourth, as Ricciardo goes fifth and Norris sixth.

As Perez goes quickest in S1, Verstappen heads out, also on softs.

Vettel (mediums) goes sixth with a 17.327.

Perez posts 16.530 to consolidate third, while Verstappen can only manage 17.435 which puts him seventh.

Albon (softs) posts 17.498 to go 14th, around 0.5s off his teammate's pace. The Thai's time is subsequently deleted for exceeding the limits at T11.

"You f****** blind, f****** honestly," asks Verstappen of Latifi, who had previously incurred the wrath of Stroll.

Meanwhile, a massive lock-up leaves Perez with a useless set of softs, the Mexican having worn his fronts down to the canvas. That could well signal the end of the Racing Point driver's session, as he will need to conserve his tyre sets for the rest of the weekend.

Leclerc posts 17.404, like his teammate, who is currently one spot ahead, he is on the mediums.

Bottas - on mediums - briefly takes the top spot only for Hamilton - on hards! - to take it back again, the Finn posting 16.089 and the Briton 16.003. With a 0.527s gap to soft-shod Perez they might as well hand the trophy over right now.

Once again silence falls on the circuit as the drivers head back to the pits. After a couple of minutes however, Stroll heads back out, followed by Sainz, both on softs as attention shifts to Sunday afternoon.

Ocon is told his pace is quicker than expected.

"Are these guys on long runs," asks Hamilton as he heads out on a fresh set of hards, Mercedes clearly doing its own thing... as it can seemingly afford to.

Reporting graining, Stroll asks what he can do about it.

As the session winds down, it's looking ominous for Ferrari and even more so for Red Bull, with - irony of ironies - Racing Point looking to be the closest thing to opposition that Mercedes faces this weekend.

"The understeer just gets worse and worse," moans Kvyat,

The session ends. Hamilton is quickest, ahead of Bottas, Perez, Stroll, Ricciardo, Vettel, Leclerc, Verstappen, Norris and Ocon.

Sainz is eleventh, ahead of Magnussen, Albon, Grosjean, Latifi, Kvyat, Giovinazzi, Russell and Kubica.

Check out our Friday gallery from Budapest, here.