Bob McFeil: ‏#bbcf1, external I can’t beat Lissie but my son can! He’s in the London Eye with the BBC Sport app open!

Kimi Raikkonen is out on softs and he lowers the benchmark by a couple of seconds and 1:20.262 is now the time to beat.

Check out Ferrari's halo additions here, the rear mirrors bolted onto them.

Image source, F1.com

Wobbly moment for Robert Kubica as that tail wind at Turn 9 catches him out a tad but he completes the lap for his first time in a session at a grand prix weekend since 2010, clocking 1:23.386.

No times yet from the Red Bulls as they continue to test out their upgrades.

Aerorake on Daniel Ricciardo's Red Bull as Max Verstappen continues to chill in the garage.

Fernando Alonso and Stoffel Vandoorne deal with that tail wind a bit better to go second and third on the timesheet, Alonso doing a 1:22.226 with Vandoorne three tenths slower.

Image source, Getty Images

Jolyon Palmer
Former Renault driver on BBC Radio 5 live

That tail wind will make it a bit snappy and Esteban did have a snappy moment there at Turn 9 on that lap.

Image source, Getty Images

First time on the board with 15 minutes gone in the session. Esteban Ocon clocking a 1:22.592.

"Tail wind into Turn 9," Ocon is told after completing that lap.

Andrew Benson
BBC Sport’s chief F1 writer

Of course the fight at the front will ultimately become the main focus of the weekend here at the Spanish Grand Prix, but as the race weekend starts, much interest revolves around McLaren.

The team have been battling to get the messaging right about the upgrade they are introducing this weekend. But after racing director Eric Boullier said that it would be the debut of their “real” 2018 car, they have been trying to keep expectations under control.

The big upgrade is indeed big, though - a dramatically different nose with all manner of aerodynamic sweeps and curves on it. It’s not exactly a looker, but it is certainly a departure - with shades of Force India but unique features, too.

Fernando Alonso said: “It’s a different circuit layout compared to the last couple of races and with upgrades everyone brings here, the same as us, hopefully we can pick up the pace a little bit. But let’s see. The most important thing is to keep scoring points on Sundays and keep helping the team to secure this fourth place in the championship.”

A nose swap for Carlos Sainz as Renault compare old and new.

Seventeen of the 20 cars have been out for an installation lap, just Max Verstappen and the two Mercedes drivers biding their time for now.

Bob McFeil‏: #bbcf1, external Good to see Kubica back in an F1 practice session. Here’s to seeing him partaking in a race soon!

Chris Marsh: Money in the "for sure" jar please Mr Kubica! Why don't Liberty Media introduce that and give the proceeds to Charity, along with Seb's swear jar.

Out goes Robert Kubica in the Williams, closely followed by Nico Hulkenberg in the Renault.

One and half hours of practice under the Spanish sun is under way.

Lissie‏, external: Right, no one had better go off! Will be listening to #FP1, external#BBCF1, external on the F1 app from the dentist's chair! #F1, external

Interesting place to be following the race, can you top Lissie's location?

You can of course listen to commentary on BBC Radio 5 live sports extra at the top of this page.

Andrew Benson
BBC Sport’s chief F1 writer

Pretty much all the teams will have upgrades of one sort or another this weekend. One of the more striking changes is Ferrari’s decision to mount their rear-view mirrors on to the halo head protection device, a change allowed by a recent technical directive from governing body the FIA.

This will be trialled in Friday practice. The idea was raised by teams on the basis it would help with driver visibility. But obviously in the background they hoped their would be an aerodynamic advantage, and it’s immediately obvious the mirrors and their mounting struts will help shape the airflow in this area.

Image source, Getty Images

Being back in Europe means we can expect plenty of upgrades on the cars.

Daniel Ricciardo has promised that not only will the Red Bull will be "quicker", but will also look "cool".

Just five minutes until we get to see for ourselves.

Image source, Getty Images

Robert Kubica using the words "for sure" there.

Still very much an F1 driver.

Image source, Getty Images

Robert Kubica, speaking to Sky Sports: "It is a good feeling, for sure. Although it is only first practice, it is good being a part of a grand prix weekend for the first time since 2010."

Thought you'd never return? "I never closed my door but for sure the percentage was very low. The last couple of years I thought, why shouldn't I try? Thanks to last year some opportunities came up.

"I just have to do my job, the initial laps will be crucial."

Andrew Benson
BBC Sport’s chief F1 writer

A momentous moment it will be, as Robert Kubica takes part in a grand prix weekend for the first time since Abu Dhabi 2010. A truly inspiring story, whatever happens in the end.