Valtteri Bottas completes a further 14 laps to move onto 64 for the morning without any improvement to his time of 1:20.596, which remains the benchmark.

Sebastian Vettel, Max Verstappen, Pierre Gasly and Kevin Magnussen are the only four drivers currently out on the track.

Dan Knutson
F1 journalist in Barcelona

Image source, .

Ferrari boss Maurizio Arrivabene stepped out of the garage to make a call. At the time, Sebastian Vettel was second, 0.014 of a second slower than Valtteri Bottas.

Sebastian Vettel produces his fastest lap of the day so far with a 1:20.610. Not quite enough to pip Valtteri Bottas, who leads the way with 1:20.596.

It was just a test to make sure people are actually reading what I'm putting in here... honest!

Andrew Benson
BBC Sport’s chief F1 writer

Also, while the test is getting going, a bit of context about the times being posted this stage. Valtteri Bottas is fastest so far on 1:20.596 on soft tyres. Lewis Hamilton set the pace last week on mediums on a 1:19.333. A senior figure told me that Hamilton’s time equated to at least a mid- to low-1:17 on the softest tyres. So there is a lot more in these cars.

And we're good to go again.

And that gravel ended up on the track because Sergio Perez had a spin.

Marshals are on the case with their sweeping brushes.

Red flagpublished at 10:27 Greenwich Mean Time 6 March 2018

10:27 GMT 6 March 2018

Second red flag of the day but it's not for a stopped car, there's a load of gravel on the track at Turn 4.

Paul Reiner: As controversial as this is going to sound, I would like to see Lewis taken down a peg and really challenged by Seb, Max and Dan Riccardo and maybe even (fingers crossed) by Nando and Stoffel...

Ashey: When was the last championship where the constructors title went to the wire? Seems along time. Rbr 4 years n merc 4 years unchallenged really

Andrew Douglas: I want to see folks other than the top 3 challenging for race wins. Bored of silver arrows consistent form.

Just over two hours gone and Mercedes have passed the 50 laps mark.

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No sign of McLaren since that power issue cut short Stoffel Vandoorne's time on the track earlier this morning.

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1) Bottas soft

2) Vettel soft

3) Gasly soft

4) Verstappen ultrasoft

5) Magnussen soft

6) Perez ultrasoft

7) Sirotkin soft

8) Vandoorne supersoft

9) Ericsson medium

10) Hulkenberg medium

Andrew Benson
BBC Sport’s chief F1 writer

Just a small observation on McLaren, following the disappointing start to their day. Last week, as usual, I crunched the numbers, spoke to team insiders, and came up with a list of what might be the potential competitive order among the teams. It informed this piece.

What I didn’t do was publish what appeared to be the specific performance level of each team, even though I have a list that has time gaps between them all in it. And the reason I did not was that it was such a truncated test that a) it didn’t seem fair; and b) I thought there was a reasonable chance it could be wildly wrong - and these things always come back to haunt you one way or another because people often ignore the careful caveats that are included. For those reasons, I am still not going to publish it now. But what I will say is that if McLaren are genuinely in the competitive position they appeared to be in that list, they will be facing some serious questions come Saturday evening in Melbourne.

There’s a fair chance the car was running in compromised form last week - first days with a new engine supplier etc. But they are going to have to show some sensible pace this week if alarm bells are not going to start ringing even louder than they already are. Especially in the context of the good form of the Toro Rosso-Honda.

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Valtteri Bottas goes quicker with 1:20.596, putting him a tenth of a second clear of Sebastian Vettel.

We've got a full compliment of times on the board now. Kevin Magnussen is currently fifth quickest after a 1:21.829 while Nico Hulkenberg is ninth (1:31.524) with Marcus Ericsson 10th (1:56.283).

I'll do a full rundown of lap times and total laps completed at 10:00 GMT.

Aaron Parsons: F1 needs a strong championship fight (both drivers and constructors) that lasts the full season. I just hope the engine penalties don’t make qualifying results meaningless as happened last year, and that we get a few wet races to really mix things up!

R Molloy: Following the #F1, external pre-season testing on the #bbcf1, external page. My big hope for 2018 is to see a genuine title challenge (and less breakdowns!) from Red Bull. Also, is there any chance @danielricciardo, external will bring back the shoey? I miss it.

Pierre Gasly improves again and he is up to third with 1:20.973. That's within three tenths of Sebastian Vettel and Valtteri Bottas with all three setting their times on softs.

Impressive from the Toro Rosso.