I'll let Mercedes answer that one, Anton...
In other words - they don't know!
Vettel's pace dropped off briefly but he's back up to the mid-1:23s as he nears the end of this run.
Kvyat is back out again in the wingless Red Bull, likely for an installation lap or two.
It's true. It's very difficult to make a red car look bad.
@ImaRedBull: He's going out for single laps here and there, which is what Red Bull has been reduced to since his unfortunate off this morning.
@RacingFan: If it had another one in Jerez it would be using it, so yes I do.
@ONZ: I agree. But then F1 seems to hate positive self-promotion.
As expected Kvyat returns to the pits after just one lap without his front wing.
For those asking about the issue which caused Hamilton to stop at the end of the pit lane earlier....
@Jacky: Nope, Raikkonen will drive the next two days.
@NikhilDuki: Not yet, no.
It's Nasr and Bottas out there on track currently.
Update for McLaren fans...
It's not raining too heavily at the moment but it is spitting. Not enough to change tyres yet
@LachuChelsea: Lots of rumour and conjecture and not a lot of hard information. The week in between Jerez and Barcelona should be when we find out what's happening.
@ShriBalaji: This current livery is for testing only. It has promised a "stronger" livery for the season itself....
Quiet has descended on the track once again.
@Graan13: Nope, no idea - McLaren is likely to keep that one under lock and key as long as possible.
The rain is putting anyone off running for the time being.
@vignesh: The team tweeted about 20 minutes ago saying it thinks it might have solved this morning's problems.
Vettel, with 45 laps to his name, decides to venture out on track once again.