That's the first day done and dusted in the final week of testing in Bahrain, before the season-opener in Australia at the start of next month.

Mercedes' George Russell set the fastest time of the day with a 1:33.459. Oscar Piastri was second-fastest in the McLaren, with Ferrari's Charles Leclerc in third.

Piastri's team-mate Lando Norris was fourth-fastest and Kimi Antonelli rounded out the top five in his Mercedes.

Thanks for joining and enjoy the rest of your evening!

See you tomorrow!

Image source, Getty Images

The last few minutes of the session involves practicing a whole heap of things including a red flag, cars going back into the pit lane and lining up in the fast lane, an extra formation lap, a standard start light procedure and so on.

Oscar Piastri (McLaren) - 70

George Russell (Mercedes) - 76

Lewis Hamilton (Ferrari) - 44

Isack Hadjar (Red Bull) - 66

Lance Stroll (Aston Martin) - 26

Carlos Sainz (Williams) - 55

Liam Lawson (Racing Bulls) - 61

Oliver Bearman (Haas) - 42

Gabriel Bortoleto (Audi) - 71

Franco Colapinto (Alpine) - 60

Valtteri Bottas (Cadillac) - 35

Sam in Lincolnshire: I thought F1 was supposed to be cutting edge technology in the motor industry and new interventions encouraged, yet when a team make a breakthrough others didn’t think of, it is squashed! Not the way to develop forward thinking business, technology or sport.

McLaren practice some pit stops for Oscar Piastri. Testing is a good opportunity not just for the drivers, but for the mechanics as well.

Haas' Oliver Bearman has just set a personal best, setting a time of 1:35.778. The Brit is 13th in the standings and has done 39 laps today.

Lance Stroll has managed to get in 26 laps after his incident earlier, which will be a relief for the Canadian. Although, the car is in the garage and the wheels are off. It looks like Aston Martin are done for the day.

Andrew Benson
BBC F1 correspondent in Bahrain

Image source, Getty Images

Formula 1 bosses are moving towards a rule change that would close a loophole rivals believe Mercedes have exploited in the sport's new engine rules.

Audi, Honda and Ferrari fear Mercedes have found a way to use thermal expansion and materials technology to exceed the mandated compression ratio.

The current rules state the maximum compression ratio of 16:1 is to be measured at ambient conditions but Mercedes are claimed to have found a way to exceed this when the engine is running at temperature.

It has now been proposed that the rule will be changed from 1 August to ensure the compression ratio is measured at a "representative operating temperature of 130C" as well as at ambient temperature.

This will now go to a vote of the power-unit manufacturers, along with the FIA and commercial rights holder F1, where it is expected to pass.

That would effectively give Mercedes the first 13 races of a 24-race season to exploit whatever advantage they may have achieved from their technology, if their engine is indeed exceeding the compression ratio at any point.

Mercedes team principal Toto Wolff insists their engine is legal and that its design has been approved by the FIA.

• Read more here

Bob in London: I watched Cars 2 over the weekend with my son. When I saw the continental cars trailing at the back and their dreadful reliability, I couldn’t help but think of Aston Martin. Sad times.

Oscar Piastri is back out on the track on a long run on the C4 compound tyre.

The Australian has been leading the pack for the majority of the afternoon session, before George Russell banked the quickest lap of the day.

Alpine have been doing some solid running today, with Pierre Gasly doing 61 laps this morning, and his team-mate Franco Colapinto on 57 so far with just over 20 minutes to the end of the session.

Image source, Getty Images

The engines will have an approximate 50-50 split in power produced by the internal combustion engine and the electrical system, up from about 20% electrical this year.

The hybrid system is simplified through the removal of the MGU-H, the complex and expensive device that recovered energy from the turbo.

Cars will have to run on fully sustainable fuel, manufactured from biomass or synthetic industrial processes.

George Russell has done 63 laps this afternoon and just went purple in sector one before setting the fastest lap of the day.

The Mercedes man set a time of 1:33.459 and goes top of the times.

Image source, Reuters

It's officially dusk in Bahrain now which is how the race would end during the grand prix weekend.

Lewis Hamilton has been released from the Ferrari garage. The Brit will be pleased to get some running in before the session ends.

He's done 27 laps this afternoon and is currently running with some flow-vis paint all over the front edges of the car.

The seven-time champion crosses the line and remains in seventh place.

If you're wondering where four-time world champion Max Verstappen is, he will be back tomorrow in the Red Bull.

His quickest time in testing last week was 1:34.798, putting him in seventh place.

Let's see what he can do tomorrow in Bahrain.

The final hour of testing is under way and Red Bull's Isack Hadjar is on a push lap on the C4 compound tyre.

He's set another personal best with a time of 1:34.260 and moves up to sixth.

The Frenchman made his Formula One debut last year with Racing Bulls' and scored a maiden podium with a third-place finish at the Dutch Grand Prix.

Andrew Benson
BBC F1 correspondent in Bahrain

Image source, Getty Images

Lewis Hamilton says he finds this year's Formula 1 cars "more fun" to drive - in contrast to Max Verstappen and Fernando Alonso's assessment of the impact of the new rules.

F1 has made the biggest rule change in its history and introduced new regulations for chassis, engines, tyres and fuel.

Verstappen has criticised the amount of energy management required from the new hybrid engines, but Hamilton said he was enjoying the reduced grip of the cars and different aerodynamic philosophy.

"We just have a less downforce," the Ferrari driver said. "But you still have to discover the grip. There's still so many elements completely under our control.

"So, it's just different, and new, and I still find it quite fun.

"The cars are more fun to drive. They're easier to correct. So you have snaps and keep them on track. The previous year's cars were a bit too on edge."

• Read more here

Seven-time world champion Lewis Hamilton is currently sitting in sixth in the Ferrari. He's only done 24 laps and hasn't come back out yet for a while now.

I will keep you updated on that one!

Joe in London: Praying for a Ferrari vs Mercedes vs Red Bull title fight. The 3 brightest talents of the current generation in Max, George and Charles up against each other with Lewis in there trying to give us one last dance for his 8th. Hollywood couldn’t write a better script!

The Cadillac livery is sure looking good during the twilight hour in Bahrain.

Sergio Perez had a lot of catching up to do in the morning session after the team took a while to get the car ready. The Mexican only managed 24 laps.

His team-mate Valtteri Bottas is currently on 18 laps with just over an hour of the session to go. He's back in the garage for now, so let's see if he manages some more laps before the end of the first day.

Image source, Getty Images

Earlier today, we asked you if you are a fan of the Cadillac livery.

342 of you like the look of the Cadillac, 160 are not big fans.

McLaren's Oscar Piastri has been posting some times on the board, but is yet to beat his fastest lap time of the day which he set earlier on.

He said last season that he preferred being "the hunted" as he was leading the world championship, before his team-mate Lando Norris knocked him off the top spot.

The Australian finished third in the end, with Red Bull's Max Verstappen splitting the two.

It really could be a blockbuster season folks!

Image source, Getty Images

Our Back at Base podcast has returned for a new series and this time we are following the new Cadillac team, plus two of last year's rookies - Oliver Bearman at Haas and Mercedes' Kimi Antonelli.

You can listen to the first episode of the new series above and you can select from all the episodes released so far here.

New episodes are released every Wednesday on the F1: Chequered Flag podcast feed.