So, today's news.

There's no lunch break (which I'm not excited about), Valtteri Bottas is fastest (which I'm mildly excited about, but not too surprised) and it is getting warmer (which I am excited about as that means we will get more drivers out on the track and not hiding away in the garages).

BBC Sport app users may need to click on the links to see the tweets.

Dan Knutson
F1 journalist in Barcelona

What power unit will Red Bull use in 2019? The team is waiting to see how good the Honda is before making a decision to switch to Honda or stick with Renault. But Renault is not going to wait around too much longer.

“We are not going to hang around forever,” said Cyril Abiteboul, the managing director of the Renault Sport F1 Team, when he met the media here in the paddock in Barcelona.

“I know what Christian (Horner) is referring to when he says that he has options,” he added. “He is absolutely right. Like him I know and read contracts. There will be a deadline for Red Bull Racing to define what they want for the future.”

When is that deadline?

“It is available, it is in the sporting regulations,” Abiteboul said. “I believe it is by the end of May when there needs to be some clarity as to who is supplying which team, which supplier is supplying which customer team. So that as far as we are concerned will be our deadline.”

So it will be a case of Renault making an offer to Red Bull who can take it or leave it?

“Yes, I guess that will be the best line for any discussion. And then there are a number of specifics that you want to have – do they want to have their own petroleum companies? Some specific dyno test programme? And so, on and so forth.”

Image source, Getty Images

I am not one to rain on anyone's parade, especially the McLaren fans who have not had too much to cheer about over the last few years, but your man has just dropped down to second in the times.

That is because Mercedes' Valtteri Bottas, who has completed 43 laps - more than any other driver today - has just regained his spot at the top of the times. His 1:20.270 is 0.055 seconds faster than Vandoorne's best of 1:20.325.

Image source, Getty Images

Some excitement for those cheering on McLaren today.

Kayleigh‍: Really REALLY!!! Hope for good things from Vandoorne this year. He's a fab driver, deserves better than 16th in the championship.

David Nutley: McLaren were nowhere for three years of pre-season testing. Even if they wanted to, they couldn't have set a 'showboating time' So this has to be seen as progress, even if Stoffel is on bubblegum tyres.

We have Valtteri Bottas, Carlos Sainz and Charles Leclerc on the track at the moment, as well as Sebastian Vettel and the Ferrari man has jumped up to third, behind McLaren's Stoffel Vandoorne and Bottas' Mercedes.

Image source, Getty Images

Mic Houghton‏: I live in Bahrain and it’s a rather mild 20-25 degrees at this time of year. Not as hot as people seem to be making out. Would be ideal for testing.

Jack Sullivan: Why is everyone moaning testing is boring? The clue is in the name.... it’s testing! Get a grip.

Hollywood23aw‏: A change of track might be a start. Set lap counts and only certain types to be used on each day. Mario Kart power ups out of the question?

Don't go downplaying the role of Super Mario Kart! Remember, Jenson Button says it helped him get going into racing. OK, so the tongue was firmly in his cheek, but listen to Button's wise words from last year below. From Super Mario Kart to the world title.

1. Stoffel Vandoorne (McLaren) 1:20.325
2. Valtteri Bottas (Mercedes) 1:20.664
3. Esteban Ocon (Force India) 1:22.907
4. Sergey Sirotkin (Williams) 1:23.327
5. Pierre Gasly (Toro Rosso) 1:24.488
6. Carlos Sainz (Renault) 1:25.059
7. Charles Leclerc (Sauber) 1:26.025
8. Sebastian Vettel (Ferrari) 1:28.510

No times from Kevin Magnussen or Max Verstappen so far. Nico Hulkenberg, Robert Kubica and Lewis Hamilton get going later on.

Dan Knutson
F1 journalist in Barcelona

The second day of Barcelona pre-season testing started at 9am CET, again in cold conditions, with some overnight frost.

The cold weather is expected to continue today and tomorrow. In these conditions, the teams decided to wait for a while before taking to the track.

This is the second day of a four-day session which will end on Thursday evening. Other points to note: the Barcelona circuit was recently resurfaced to make it smoother. During yesterday’s testing, the top two times (set on the medium tyre) were faster than the fastest medium time set during the equivalent test last year.

Another four-day session will start next Tuesday 6 March to end on Friday 9 March.

Image source, Getty Images

Alex Withington: I'm a huge McLaren fan but I was wondering if they would indulge in some showboating early on in testing to attract some more sponsors for 2018. Fingers crossed this pace is real.

So cynical Alex. You could get a job here.

Remember, Stoffel Vandoorne is the fastest man so far today, with a benchmark time of 1:20.325.

Image source, Getty Images

A little diversion into the gravel for Kevin Magnussen. He has only been out for two laps in total today. In one of them he went off. Nothing too serious though, but he is back in the garage.

BBC Sport app users may need to click on the link to see the tweet.

MS_MUFC: I do think Mclaren can go even quicker if there cars weren't painted in Orange.

Moon Quddus: Got an wild idea to make F1 testing more exciting. What if... they place a bunch of cameras round the track, record the cars going round, and then televise it (to broadcasting companies and streaming services) as it's happening? Crazy plan, right?

Viva la revolution.

Right you lot, a lot of people have not been too excited by what we have seen so far today. So the stage is yours.

Tell me how we can improve testing? What would you keep, what would you change?

Tweet us using the hashtag #bbcf1 and we will stick those comments in this page

So far today, Sergey Sirotkin has had 19 laps out on the track, but none of them timed.

Image source, Getty Images

Dan Knutson
F1 journalist in Barcelona

About 50 journalists showed up for a press conference with Williams deputy team principal Claire Williams in the paddock.

Asked about the team’s new driver Sergey Sirotkin, she said that he had only had a brief stint in the car yesterday as Williams is doing half-day shifts with its driver line-up.

“He is a lovely guy,” she said. “He is going to impress people this year. I know it is early days and we have to wait and see. It will be a learning curve for him in his first season. But everything I have ascertained from him so far is that he is incredibly keen to prove his talent. He is working well with our engineers, he is incredibly intelligent, he has a degree in engineering. And that is going to really help drive the team forward.

“He is working well with Lance and Robert. We have to wait and see until we get to Australia. But last year people really had him on their radar, and our driver announcement came as a surprise to people. But if we didn’t have the faith in him that he could deliver we would not have put him in our line-up.”

Image source, Dan Knutson

Matt Gamblin: Might be worth noting that Vandoorne's lap was on hypers.

Simon Anderson: Why, oh why, haven't McLaren matched their halo in with the colour scheme? Their car looks great but the halo looks worst on theirs because its plain black.

Dan Knutson
F1 journalist in Barcelona

Robert Kubica is back in the paddock and will be a regular this year in his role as test/reserve driver at Williams.

He goes this afternoon.

Image source, Dan Knutson

Image source, Dan Knutson

So Stoffel Vandoorne is a surprise leader. How good was his lap? Well, as a comparison, only Daniel Ricciardo has gone faster in a day and a bit of testing.

Ricciardo's best lap yesterday was timed at 1:20.179.

Image source, Getty Images

Alonso was seventh fastest yesterday, and we were not expecting this, but Stoffel Vandoorne has just go fastest.

He has just set a time of 1:20.325. Very positive signs for McLaren.

Here, courtesy of McLaren's Twitter feed, is a Gif of Vandoorne's cockpit routine.

Now we're getting going. Bottas just goes even faster, 1:20.806 is now his best.

As a comparison, his best lap yesterday was 1:20.349, while the fastest overall was Daniel Ricciardo's 1:20.179.

Stoffel Vandoorne has become only the third driver to set a time, and comes up with 1:23.443.

All that waiting around, now let the games begin.

Image source, Getty Images

Ladies and gentlemen, boys and girls, we have a new fastest driver. Valtteri Bottas of Mercedes zooms round in a time of 1:21.194.

Only him and Carlos Sainz have set recorded laps, with Sainz' best being 1:25.059

How many laps have they done so far...

At 10:50 GMT, this is who has the done the most laps

• 20 Valtteri Bottas (Mercedes)
• 18 Sergey Sirotkin (Williams)
• 12 Charles Leclerc (Sauber)
• 9 Stoffel Vandoorne (McLaren)
• 8 Carlos Sainz (Renault)
• 5 Pierre Gasly (Toro Rosso), Sebastian Vettel (Ferrari), Esteban Ocon (Force India)
• 1 Kevin Magnussen (Haas), Max Verstappen (Red Bull)