McLaren CEO Zak Brown is on the pit wall in the sunshine today. The American is chatting to Sky Sports about the contract extension for Oscar Piastri and the topic of team orders comes up once again.

The last thing the constructors' champions need is their drivers taking points off each and lengthy team radio negotiations like we heard last year in Hungary, so are 'papaya rules' back for 2025? "Of course!" says Brown. "Quite simple, respect your team-mate, race each other hard but give each other space," he adds.

Meanwhile, George Russell says he is hot inside the car...

1. Charles Leclerc (Ferrari) - 1:17.880

2. George Russell (Mercedes) +0.150

3. Isack Hadjar (Racing Bulls) +0.338

4. Lando Norris (McLaren) +0.373

5. Max Verstappen (Red Bull) +0.445

Andrew Benson
BBC F1 correspondent in Melbourne

Lewis Hamilton has been oozing positivity all winter about his move to Ferrari but one of the things he has been saying between the positivity is that "I am still going to have to get used to the team and the car". It does look like that because he has been consistently slower than Charles Leclerc on every lap he has done so far, just over half a second back at the moment.

The giant hoover has been out to remove the gravel, so cars are now heading out to continue their running in this opening practice session.

Just before the red flag, George Russell, the new leader of Mercedes following the departure of Lewis Hamilton, was on the radio to his pit wall to highlight issues with understeer around Turns Nine and 10.

Red flagpublished at 01:52 Greenwich Mean Time

01:52 GMT

So the red flag is for gravel on the track kicked up by the Alpine of Jack Doohan.

Image source, Reuters

Red flagpublished at 01:51 Greenwich Mean Time

01:51 GMT

The timesheets tell us there is a red flag. Not that I know what it's for...

Isack Hadjar is a rookie that could provide us with some great entertainment this year. The Frenchman has been talking about his love for Lewis Hamilton and confessed he was slightly sweaty at the thought of meeting his idol during the drivers' photoshoot a few weeks ago.

Hadjar narrowly missed out on the Formula 2 championship last season to fellow rookie Gabriel Bortoleto and he's put a stellar lap time down in first practice to go third on the timesheets, just over three-tenths off the time of Charles Leclerc.

The spotlight has been firmly pointed in the direction of Lewis Hamilton since arrival at Ferrari, which has left Charles Leclerc somewhat on the sidelines.

This pairing is arguably one of the strongest we've seen in years, with the two predicted to be closely matched throughout the season. Who would you put as number one driver if a team orders situation popped up?

For now, Leclerc has started brightly for the Italian team, clocking the fastest lap on the mediums with a 1:17.880 followed by the Mercedes of George Russell and McLaren's Lando Norris.

Image source, Reuters

Liam Lawson is a rookie with 11 grands prix under his belt, so a lot more will possibly be expected of the New Zealander compared to the greener newbies on the grid. Partnering Max Verstappen at Red Bull is also a job that is less than enviable, but as long as the 23-year-old puts consistent points on the board to aid Red Bull's constructors' fight, he should be fine.

Lawson gives us the first team radio of the year, telling his pit wall he's just had a slight touch of the wall at Turn Nine.

Image source, FIA

You may think it's far too early to bring updates to a race weekend, as we haven't even started yet, but you'd be wrong.

McLaren, Ferrari, Mercedes and Red Bull have all brought updates for the Australian Grand Prix, with Red Bull in particular submitting a long list including of 15 performances upgrades.

The rest of the grid - Aston Martin, Alpine, Haas, Racing Bulls, Williams and Sauber - are also on the update list.

Andrew Benson
BBC F1 correspondent in Melbourne

Ferrari are not just the most successful team. They are the most iconic, the most legendary, the most historic team in Formula 1. Ferrari surpasses everything, Ferrari is Formula 1 and Lewis Hamilton going there has sent interest in this season completely off the scale. Some of the numbers we have been seeing on the BBC Sport website almost beggar belief.

The medium tyres are bolted on across the field for this opening session in Melbourne, including Ferrari's Lewis Hamilton, who is decked out in red with his yellow race helmet.

If you're watching along this season, the seven-time world champion's T-cam is also yellow on his car.

Hamilton slots into fourth on the early timesheets as Max Verstappen puts down the first marker of a 1:19.771 in the Red Bull.

Image source, Reuters

Following Pirelli's decision to go softer with the tyre allocation in Melbourne last year, the Italian supplier has opted to stick with the same compounds for the 2025 event this weekend, which are the C3 (white, hard), C4 (yellow, medium) and C5 (red, soft), as well as the green intermediates and blue full wets, should they be required (which they might).

The semi-permanent street circuit at Albert Park has not changed since its revamp in 2022 and the most popular race strategy last season was a two-stopper, with the hard tyres putting in the majority of the graft over 58 laps.

Start your engines, folks. The first practice session of the 2025 season is green.

Image source, Getty Images

BBC Radio 5 Live Sports Extra

Greetings for the first time this season to the commentary team out in Australia. Rosanna Tennant, Harry Benjamin, former McLaren mechanic Marc Priestley and F1 correspondent Andrew Benson will be taking us through the whole weekend at Albert Park.

Full commentary is available on BBC Radio 5 Sports Extra, BBC Sounds and at the top of the page using the 'listen live' tab.

You can also listen via most smart speakers by asking BBC Sounds to play Australian Grand Prix, followed by the current session.

Image source, Getty Images

Here are your 20 drivers for the new season. In bold are the ones who are starting a fresh chapter with a team.

Haas and Sauber have revamped their full line-up, while McLaren and Aston Martin have stuck with the tried and tested.

Alpine - Pierre Gasly and Jack Doohan

Aston Martin - Fernando Alonso and Lance Stroll

Ferrari - Charles Leclerc and Lewis Hamilton

Haas - Oliver Bearman and Esteban Ocon

McLaren - Oscar Piastri and Lando Norris

Mercedes - George Russell and Andrea Kimi Antonelli

Red Bull - Max Verstappen and Liam Lawson

Racing Bulls - Yuki Tsunoda and Isack Hadjar

Sauber - Nico Hulkenberg and Gabriel Bortoleto

Williams - Alex Albon and Carlos Sainz

Image source, BBC Sport

There are plenty of fresh faces joining the grid in 2025, with six rookies - the most since 2001- taking to the track for the new campaign.

The youngest of the bunch is Andrea Kimi Antonelli, an 18-year-old Italian who has been a Mercedes protege since the age of 11 and is stepping up to the seat left vacant by Lewis Hamilton.

Oliver Bearman is the other teenager in the group and after three super-sub appearances last season, the Briton is now making his debut with Haas.

Liam Lawson is a driver we all know well. For his first full campaign in Formula 1, the New Zealander is partnering four-time world champion Max Verstappen at Red Bull.

Sauber have signed back-to-back F2 and F3 champ Gabriel Bortoleto, Racing Bulls welcome F2 runner-up Isack Hadjar and Alpine will have plenty of Aussie support this weekend thanks to new driver Jack Doohan.

The weather in Melbourne is famously unpredictable. 'Four seasons in one day' is how it's often described.

Today's session is set to be pleasant and dry, followed by beautiful sunshine and very warm temperatures for Saturday's opening qualifying session.

Sunday's race, which starts at 4am UK time (3pm local), is forecast to be a lot cooler with the rain arriving in the morning and easing towards lights out.

Image source, Getty Images

Have McLaren got the best driver line-up on this year's grid, as Zak Brown claims?

Obviously, the most notable change for 2025 is Lewis Hamilton to Ferrari. It feels like we've had to wait an eternity to see the seven-time world champion race for the Scuderia, so the anticipation is sky high to see what he can do on his first competitive outing. His pairing with Charles Leclerc is also one to watch.

Carlos Sainz at Williams is another eye-catching signing. The Spaniard, who was winner in Melbourne last year, has said the chances of him fighting for podiums are very slim, but you never know. Throw in a rain-affected race like Brazil 2024 and anything could happen.

He could even get that opportunity on Sunday...

Image source, Getty Images

The first big news of the weekend belongs to home driver Oscar Piastri, who has signed a new long-term contract with McLaren.

Australian Piastri, who won two races last season and finished fourth in the drivers' standings, was already contracted to the end of 2026.

McLaren Racing chief executive officer Zak Brown said the 23-year-old had shown he is an "incredibly talented driver" and "an asset" both on and off track during his two years with the team.

Brown also said McLaren "have got the best driver line-up on the grid".