Pierre Gasly is back in the pits pretty sharpish. His race engineer says there is an issue, so the Alpha Tauri gets pulled into the garage for further inspection.

First time on the board to get us started. A 1:23.641 for Norris.

Lando Norris has come out on a set of medium tyres.

How are we looking for today's final practice and qualifying? Update from BBC weatherman Ian Fergusson:

"Air temperature 30.5C and track 42C. Southerly breeze; gusts ~15mph. By qualifying, air temperature likely 32C: markedly above average, with tomorrow potentially nudging 35C. Almanac below shows previous qualifying conditions since 2016.

Image source, .

Norris is joined by team-mate Daniel Ricciardo, Pierre Gasly and Lance Stroll for an early run out.

Hola Lando Norris. First out on track with a new chassis.

I'm rubbered in. Are you? Off we go.

BBC Radio 5 Live Sports Extra

Commentary is online-only for this final practice session.

Jack, Jennie, Marc and Andrew are waiting for your company at the top of the page.

Most of the post-practice talk on Friday - accusations of copying aside - centred on the pace of the Mercedes cars. Drivers and team personnel were clearly delighted with the steps taken, but tempered their enthusiam with warnings about not getting carried away, especially with Miami's false dawn in mind.

But where do you think Mercedes are right now - more of the same or genuine players at the front of the grid again?

Get in touch with us on this - or indeed any topic - using the Twitter hashtag #bbcf1

Andrew Benson
BBC Sport’s chief F1 writer

Aston Martin were the talk of the paddock on Friday, after Red Bull accused them of copying their car, and raised questions as to whether it had been done entirely legitimately. That aside, the massive upgrade - which did, it has to be said, look like a pretty full-on copy of the Red Bull - did look promising, with Sebastian Vettel ending Friday eighth quickest.

“We are confident this is the way forward,” the four-time champion said, “but it is the first day we are out with a new car. Lots to learn. For that it was good. We were in the top 10, which was strong.

“I guess it will be very tight. You can’t expect miracles yet. It is a long way and we knew it is not going to be a big step forwards straight away. We kept the window open very early in winter to e able to adapt the car. We had more or less two concepts, we started with one and switched to the other one.”

Chief technical officer Andrew Green said on Saturday:

“This car didn’t just evolve in the middle of last month, this car started development in the middle of 2021. We have been understanding of and trying to develop this car for many months. It isn’t the case of copying without understanding. This was genuine independent development that came to a very similar conclusion in a specific area of the car.”

Image source, Getty Images

Do these two cars look similar?

According to Red Bull team principal Christian Horner, while imitation is the sincerest form of flattery, nicking an organisation’s intellectual property is not.

Aston Martin said the FIA had confirmed it was "legitimate independent work".

You can read the full story on the Red Bull versus Aston Martin showdown here.

The green cars of Sebastian Vettel and Lance Stroll didn't exactly wow us all on Friday, but if they pull a rabbit out of the hat for today's qualifying session, expect to hear a loud knock on the stewards door come the chequered flag...

Image source, Getty Images

Andrew Benson
BBC Sport’s chief F1 writer

What to make of Friday at the Spanish Grand Prix? Charles Leclerc was quickest in the Ferrari. No surprise there. But the Mercedes of George Russell and Lewis Hamilton were second and third, quick like they were in Miami. But in Miami it was a mirage. Is it real this time? Max Verstappen, meanwhile, was down in fifth on single-lap pace, but hugely impressive on a long run. Ferrari need to go one way with their car; Red Bull another. And where will Mercedes end up? It’s an intriguing way to enter the weekend.

Image source, Getty Images

Although, Lewis Hamilton is looking on the brighter side of life when it comes to Mercedes' upturn in fortune.

"It is positive," said Hamilton. "I am super happy with the progress. We're not the quickest yet but I think we're on our way."

The 37-year-old also commented on the car's smoothness during Friday's practice runs, saying he was grateful for the upgrades and the team "just need to fine-tune them."

He added: "It is the first time we have driven down the straight without bouncing. We still have some bouncing but it is way better and we are starting to eke into the potential of the car.

"It is still tough but it is much nicer than it has been before."

Image source, Getty Images

Proceed with caution is the motto George Russell and the Mercedes team are sticking to in Barcelona.

"In Miami we were quickest and then here we are second, so let's see," Russell told Sky Sports.

"The car is definitely reacting differently. We've got different limitations this time. We definitely don't have the porpoising in the straight - which is is good - but we're still experiencing it here and there in the corners.

"I still think Red Bull look very strong; they look the team to be reckoned with at the moment, so we need to look through the data."

Thousands of Spanish supporters are packing the stands over the course of the weekend to catch a glimpse of home driver Carlos Sainz.

Ferrari's Sainz was second to team-mate Charles Leclerc in first practice but found the running a tad frustrating later on in the afternoon.

Andrew Benson
BBC Sport’s chief F1 writer

Image source, Getty Images

Sitting pretty at the top of the times he may have been, but Charles Leclerc was far from content on Friday evening. “There is a lot of work to do,” the championship leader said. On the short run we looked strong, but the high-fuel run looks very difficult for now. We will have to find white a bit of pace for tomorrow. It is definitely the priority to work on that because at the moment we are just not strong on race pace.”

Ferrari team-mate Carlos Sainz said the upgrades Ferrari have taken to Spain were working, but that the team went backwards between the first and second practice sessions “and made ourselves slower”.

The Ferrari was quick in the final sector - which is good news for them, as the upgrades were intended to improve slow-corner performance, one of the areas where Red Bull have had an advantage so far this year. But as Sainz pointed out: “At the same time, Mercedes and red Bull were also quick in the corners today.”

Image source, Getty Images

Two quickest times on the board for Charles Leclerc yesterday.

The 24-year-old Ferrari driver clocked 1:19.828 a in the first session and then went just under two tenths quicker in Friday's other outing.

Leclerc claimed his 12th pole position of his career at Miami's debut two weeks ago and is looking for his fourth front-row spot of the season.

But was he actually happy with yesterday's performance?

Image source, Getty Images

First practice had a Ferrari flavour to it as Charles Leclerc lead the way, followed by team-mate Carlos Sainz in second.

The Red Bull of Max Verstappen was third, Mercedes' George Russell was fourth and Spaniard Fernando Alonso was fifth.

Next up, Leclerc was again frontrunner in the Suderia but this time, instead of of his buddy Sainz alongside him, it was the two Silver Arrows - George Russell second and Lewis Hamilton third - that completed the trio of quickest drivers.