Few more times coming in now with 20 minutes gone. A power slide coming through a corner costs Kimi Raikkonen a bit of time and his first effort is almost two seconds slower than Lewis Hamilton. His time was also done on the ultrasofts and puts him P3.

Valtteroi Bottas has super softs on and goes fourth quickest with a 1:50.404. That's a further second down on Hamilton's benchmark time.

Now here comes Lewis Hamilton for a fast lap... and he goes half a second quicker than his team-mate.

First blood to the Briton.

Image source, Getty Images

A box of ice. Vital in Singapore.

Nico Rosberg sets the first flying lap of the session so far - clocking a 1:47.936 on the ultrasofts. That's already faster than the time he clocked to top P1 last year - a 1:47.995.  

Jenson Button is back in the pitlane and the virtual safety car period is over. 

Lewis Hamilton, with the halo on his Mercedes for the first time this season, heads out with ultrasofts bolted on. That's the tyre of choice for most of the other drivers as well.

Image source, Rex Features

Jenson Button will have a bit of time on his hands now as McLaren look to get to the bottom of this problem.

I tell you what he won't be doing while he waits - playing Pokemon. 

He filmed the above video earlier this week, utterly perplexed by a load of people staring at their phones playing the game that has turned into a global phenomenon.

"All of these people were walking one way, and do you know why? Pokemon," he said.

"There must have been 2,000 people all walking to one spot - through the shopping mall and across the road - because there is a Pokemon to grab. Come on. Is Formula 1 not more interesting than that? It should be. I think it is. 

"But if they can get that many people interested in trying to flick something at a yellow dot that is not really there, I think we can make Formula 1 better than it is."

A couple of marshalls scurry over to Jenson Button's McLaren, which stopped around 200m from the pit entrance, and proceed to roll it home very, very slowly.

Three-and-a-half minutes into the session and the McLaren of Jenson Button has just rolled to a halt. 

"Yes it has stopped," he sighs. "Not going to make it back to the pits."

Everyone has been out to get a feel of the circuit, apart from Lewis Hamilton and Nico Rosberg.

Tom Clarkson
BBC Radio 5 live commentator

This is one of the less power hungry tracks on the calendar, certainly compared to Monza and I think Red Bull can expect to be more competitive this weekend. Daniel Ricciardo really shines on this kind of track.

No floodlights on just yet in Singapore with the sun still in the sky as the cars head on out for 90 minutes of first practice.

Andrew Benson
Chief F1 writer

Image source, Getty Images

There is nothing quite like Singapore - and it has to be witnessed first hand to truly appreciate it. On television, Singapore looks pretty enough, but the race can be a little dull. When you are there, though, it’s a terrific weekend. The crushing heat and humidity fades a little as the sun goes down, the whole place sparkles as the lights come up, the track - long, technical, bumpy, walled - really tests the drivers. The time-slip schedule that forces F1 people to wake at lunchtime, work into the early hours and go to bed at dawn adds a surreal twist. It is, in a word, wonderful. 

It appears that Fernando Alonso, Lewis Hamilton and Nico Hulkenberg will have the halo on in this session. 

Five minutes until the track is open.

With the drivers not getting to the circuit until the afternoon in Singapore they get the rare luxury of a lie in or, in Kevin Magnussen's case, more gym time.

Andrew Benson
Chief F1 writer

Image source, Getty Images

It’s well known that Singapore is the toughest race of the season - the heat and humidity, combined with the city location, bumpy tracks, close walls and almost two-hour race making a hellish mix for the drivers. 

Daniel Ricciardo said: “It’s the toughest, sure. It’s similar heat and humidity to Malaysia but you’re surrounded by just the city and a lot of concrete, so it’s the one race I feel where you open your visor to get some air and you’re not getting any reward for that. It’s just heat and stale air. In Malaysia there’s a bit of circulation: even though it’s hot, you get a bit of a breeze but here, no. It’s a track that you can’t… if you come here unprepared, then you can’t luck into a good result. You’ve got to come ready to go.”

Force India’s Sergio Perez added: “The last 10 laps, 20 laps, you’re really praying for a safety car because it’s just really hard to finish the race, physically. And mentally as well. Mentally it’s a very big challenge because every corner, most of the corners, if you do a mistake you just touch the wall and it’s a puncture or something like that.”