Red flagpublished at 13:30 BST

13:30 BST

A red flag with just a minute left on the clock.

Sergio Perez' Cadillac comes to a halt on track.

Given the time, this could affect those who want to do a practice start after the session officially comes to an end.

Three minutes left in the session and it's not looking like anyone's going to top Kimi Antonelli's 1:07.796.

Other than his Mercedes team-mate George Russell, only Oscar Piastri has been able to get into the 1:07s.

Andrew Benson
BBC F1 correspondent

It's Lewis Hamilton who looks a bit out of sorts currently. He's six tenths off Kimi Antonelli's pace-setting time in fifth place in the Ferrari. And that's on the soft tyres as well.

But it's only first practice. We don't know fuel loads, etc, etc.

David: Lewis can do it, Ferrari can take the constructors' title, but it will take a 100% perfect run from everyone in the team.

Dan: Historically, the European leg of the season is where Lewis has really put his foot down (Silverstone, Spa, Hungary, Monza). With his strength at these circuits and experience of chasing the leader, only a fool would rule him out.

Lando Norris' first effort on track results in a seventh-fastest finish with a 1:08.873.

He is a bit of an outlier in the top 16 in that he's set that on the medium tyre rather than a set of softs, however.

Abbie Eaton
British racing driver on Sports Extra 2

Picking a number one driver is a tough decision for a team to make. I think both Charles Leclerc and Lewis Hamilton are quite nice in the way they operate; I kind of get the vibe that between them, it's a bit like 'after you, no, after you' to a certain degree.

But, Lewis is second in the championship at the moment, so you would have to argue if that continues moving forward, it's going to have to be Lewis.

1. Kimi Antontelli (Mercedes) - 1:07.796

2. George Russell (Mercedes) +0.040

3. Oscar Piastri (McLaren) +0.117

4. Max Verstappen (Red Bull) +0.281

5. Lewis Hamilton (Ferrari) +0.665

Harry Benjamin
BBC F1 Commentator

Lando Norris is emerging from the pits with 14 minutes on the clock. McLaren have been fixing a suspected hydraulics issue on the car, consigning him to the garage for the majority of this session.

McLaren will be hoping to get some data on that new rear wing that they're running.

Lando Norris finally get out on track having lost 45 minutes in the session.

What can he do with the remaining time left in FP1?

All but one driver has got out on track with Lando Norris still confined to the garage.

15 minutes left for McLaren to get him out.

Ferrari have deployed the soft tyre to Lewis Hamilton's car and he goes third fastest with a 1:08.549.

Kimi Antonelli continues to lead the way with a 1:07.796, just 0.040 seconds faster than George Russell.

The two Mercedes cars are the only ones to breach the 1:07.000 barrier so far.

Vadim: McLaren cannot give Lando a reliable car. Every race weekend there is an issue - it’s getting beyond frustrating. The fans at Silverstone won’t be happy next weekend if this is what they will see.

There's a bit of a jumble of different tyres being used today as the teams try to gauge the high track temperatures.

As it stands, the current top five have all set their respective times on softs.

Abbie Eaton
British racing driver on Sports Extra 2

This is not what you want [issues for Lando Norris and Max Verstappen] to have in free practice one, especially with things on board that you are trying to test out. It could be these high temperatures; there are a lot of drivers complaining about a lack of grip, so it could just be the tyres are struggling in these temperatures.

So then, midway through the session and Kimi Antonelli leads the pack.

However there's been some mechanical issues for Lando Norris - who's yet to get out - and Max Verstappen who launched his Red Bull third fastest despite twice coming to a halt in the pit lane.

1. Kimi Antonelli (Mercedes) - 1:07.796

2. George Russell (Mercedes) +0.119

3. Max Verstappen (Red Bull) +1.096

4. Oscar Piastri (McLaren) +1.175

5. Nico Hulkenberg (Audi) +1.369

Nicholas: Hamilton is fit, so the heat won't worry him. He's working well with his engineer, and the circuit requires precision. Oh, and you can overtake!

KG: Austria is a weak track for Lewis and if Ferrari can arrive here and he can fight the Mercedes. That’s where hope can start to manifest. For now it’s pure enjoyment for LH fans.

"I have very little feeling, basically. It's just...tyres feel hot and no grip" Max Verstappen says of his Red Bull over the team radio.

Likewise Lewis Hamiiton says it's a struggle out there.

The heat is certainly making its presence felt in Spielberg.

Harry Benjamin
BBC F1 Commentator on Sports Extra 2

Max Verstappen's Red Bull is struggling out there.