As a reminder, in terms of upgrades, McLaren has a new Sidepod Inlet, Coke/Engine Cover, Cooling Louvres, Floor Edge, Diffuser, Rear Suspension and Rear Wing.

The sidepod inlet has been revised aimed at improved flow conditioning towards the rear of the car for improved aerodynamic performance, while the engine cover and coke line have been revised in conjunction with the new sidepod inlet enhancing the flow conditioning downstream. An alternative sidepod shape is available as an option for the aforementioned bodywork, resulting in a change of resultant aerodynamic properties.

As part of the new bodywork package, the cooling louvre layout and position have been altered for maximum aerodynamic performance at various cooling levels. The flow conditioning changes from the bodywork are utilised by a revised floor edge design, resulting in improved aerodynamic performance, while in conjunction with the floor edge, the diffuser has been revised, aimed at extracting more aerodynamic performance from the new flow topology. The changes in upstream aerodynamic flow conditions incentivise a modification to the rear suspension fairings to maximise aerodynamic performance, while the medium isochronal rear wing has been modified to deploy the flap to an alternative position in straight line mode, resulting in a larger reduction in drag.

Red Bull has a new Floor Body & Diffuser, Sidepod, Cooling louvres, Mirrors and Halo. The realisation of development iterations sees a new floor geometry with subtle changes within the permitted geometry to extract more local load whilst maintaining flow stability. Accompanying the new floor, the sidepod has been revised with a new junction or split line to the floor, to supplement the floor changes yielding more local load. To blend the new sidepod to existing surrounding geometry, the cooling louvres have been revised whilst maintaining the range of cooling levels offered previously. Also accompanying the floor and sidepod, the mirror assembly geometry has been revised to aid the downstream conditioning and supplement the local load increase, while a small change to revise a turning vane on the fairing is to better serve downstream components, the flow stability and therefore load generation.

Other than the much-anticipated new, significantly lighter tub, Williams has a new Floor, Tail, Front Corner, Rear Suspension and Rear Corner. The Grove outfit has modified the forward and outboard regions of the floor to extract more performance both locally and across the main underfloor surfaces, while the revised tail geometry has been introduced to suit the floor update. The new surfaces work together with the new floor to generate increased performance locally around the rear impact structure (RIS).

The forward and rearward regions of the front wheel bodywork have been updated to offer both improved interaction with the front wing and an improved downstream flow field with the rest of the car, while, to suit the new onset flow, the surfaces on the rear suspension have been realigned to offer additional performance in the rear corner. The previously described geometry changes have unlocked a new flow field opportunity in the rear corner and Williams have been able to extract additional performance in this region by retuning these devices.

Racing Bulls have a new Front Wing, Front Corner and Front Suspension. The new front wing geometry helps establish a clean flow field, which leads to improved performance from the components downstream of it, while, working in conjunction with the new front wing, the front corner & suspension updates help manage the flow downstream and around the car, allowing the floor to perform effectively.

Audi has a new Front Wing, Front Wing Endplate, Nose, Front Suspension, Floor Body, Floor leading edge devices, Diffuser, Halo, Coke/Engine Cover, Rear Suspension, Rear Corner, Beam Wing, Rear Wing and Rear Wing Endplate.

A full new front wing is being introduced alongside an updated nose fairing to deliver a better flow to the rest of the car while covering the balance levels of the new package. The front suspension fairings have been revised to complement the revised front wing and nose and support the aerodynamic intent of the new package. A new floor is introduced for this event, all surfaces are new and designed to deliver a consistent load increase.

The revised bodywork and associated cooling options have been introduced to work with the updated package and improve management of the downstream flow structures, while the rear suspension covers and brake duct elements have been revised to complement the updated rear end flow field and improve aerodynamic performance. Finally, the revised rear wing assembly features updated elements designed to operate as part of the overall aerodynamic package.

Cadillac has a new Front Corner, Front Suspension and Diffuser. The front corner geometry has been revised to increase the available brake cooling capacity, whilst maintaining flow quality to the rear of the car, while the front suspension fairing surfaces have been updated to retain compatibility with the updated front corner and brake duct geometry. The profile of the lower shedding edge of the rear diffuser winglet has been updated to increase local aerodynamic load across the operating envelope of the car.

Mercedes, Ferrari, Aston Martin, Haas and Alpine do not have any updates this weekend.

Russell was quickest earlier, teammate Antonelli sidelined early on with a hydraulics issue. An over enthusiastic marshal liberally covered the car in extinguishant and as a result the team has had to change the Italian's engine.

The world championship leader was one of several drivers to lose track time due to various issues. Both McLarens had problems, as did Sainz and Hulkenberg, while Hadjar also missed much of the running.

Brakes appeared to be one of the major factors, and based on what we've seen thus far Sunday could be a race of attrition.

Ahead of the green light, the air temperature is 30 degrees C, while the track temperature is 48 degrees. It remains bright, sunny and warm.

The lights go green and Gasly leads the way, followed by Bottas, Russell, Lawson and Perez.

As more drivers emerge most are on mediums, though Alonso is on softs and a couple of others are on hards.

Colapinto runs wide in Turn 1 and heads down the escape road.

Of the first wave, Russell goes quickest with a 46.300, ahead of Lawson and Gasly.

Quickest in S1, Verstappen crosses the line at 45.933, ahead of Russell, Hadjar and Gasly, though the Alpine driver is subsequently leapfrogged by Norris who posts a 46.448.

Norris goes top with a 45.184, on the hard, but is leapfrogged by medium-shod Verstappen (45.115).

Leclerc goes third on the mediums, ahead of Russell (medium) and Piastri (hard).

Ten minutes in and Lindblad heads out, leaving Antonelli as the only driver yet to appear, Mercedes claiming that it will be another 20 minutes before we see him.

Russell retakes the top spot with a 44.537, having been quickest in the first and final sectors.

Moments later, quickest in the second sector, Verstappen posts a 44.492.

Replay shows Lawson masterfully controlling a slide that almost took him into the barriers.

PBs in all three sectors see Hamilton improve to fourth, albeit 0.757s off the pace.

A 45.462 sees Hadjar slot into fifth.

The session is red-flagged when Lindblad hits the wall at Turn 8 with his rear-right.

"Sorry, I crashed, really sorry," he tells his team.

Replay shows that after clouting the wall he hit it again as if to make sure. He makes it to Turn 11 in order that he can park the damaged RB safely.

The session resumes with 31 minutes remaining, among those in the pitlane awaiting the green light, is Antonelli.

Bottas leads the way, followed by Colapinto, Perez, Gasly and Bearman.

"Oh, **** my engine broke," reports Bearman as he stops at Turn 2. Replay shows his engine cut-out the moment he left the pitlane.

"Similar to Zandvoort, sorry guys," says the Haas driver.

On his first flying lap, Antonelli goes sixth with a 45.671, the Italian on softs.

Gasly momentarily stops before he is able to get going again.

As Piastri goes purple in S1, Leclerc goes top with a 44.473. Piastri stops the clock at fifth following a poor final sector.

Quickest in the final two sectors, Russell goes top with a 43.759, like everyone else the Mercedes driver is on softs.

Gasly goes tenth and Hamilton fourth, as Hamikton closes to within 0.415s of pace-setter Russell.

Perez, courtesy of a tow from Lawson, goes eleventh with a 45.760.

"Dude, that was dangerous," says Lawson after coming across a slow Hamilton, "oh my God, really dangerous."

As it is revealed that Hamilton will be investigated, Piastri has a big, big slide but avoids the barrier.

Russell consolidates his top spot with a 43.347, putting 0.827s of daylight between himself and Verstappen.

A 43.899 puts Antonelli go second, 0.552s off his teammate's pace.

"****, I almost went into the back of Bortoleto," complains Russell.

Currently 22nd, Alonso is thought to have an oil leak.

Though fourth and fifth, both Ferraris are currently over a second off the pace, the SF-26 clearly lacking straight-line speed.

Attention has now switched to Sunday, with Norris setting a strong pace.

Gasly is currently seventh, ahead of Piastri and Hadjar.

A number of drivers have had times deleted for track limits violations, Turn 15 being the scene of a majority of the errors.

Norris appears to clip the wall but is able to continue.

The session ends. Again, Russell is quickest, ahead of Antonelli, Verstappen, Leclerc, Hamilton, Norris, Gasly, Piastri, Hadjar and Ocon.

Colapinto is eleventh, ahead of Lawson, Perez, Bortoleto, Hulkenberg, Albon, Sainz, Lindblad, Bottas, Bearman, Stroll and Alonso.

Impressive stuff from Russell, but so too from Antonelli who missed at least half of both sessions.

However, as we said earlier, and having seen nothing to contradict the feeling over the last sixty minutes, this is going to be a weekend of attrition, and consequently we can expect a few surprises.