Good morning and welcome to coverage of the final free practice session for the Spanish Grand Prix. "Another glorious morning at the Circuit de Catalunya. It's meant to be cooler today but at 21C already it doesn't feel like it" is how conditions are described by Laurence in the paddock on our Twitter feed @ESPNF1

We're expecting a relatively busy session as teams try to work out how to get the most out of the two tyre compounds. With both the hard and the soft available the difference is larger than it has been so far this season - around 1.5s per lap - but that means it's tough to get a car that works on both tyres

As always with these sessions we'd love to hear from you. We may only have an hour of running but we'll attempt to answer as many questions and publish as many comments as possible. You can either email us using the link above or get in touch using the Twitter link below

This shot from FP2 is pretty representative of the current weather in Barcelona:

© Sutton Images

A few engine facts from Renault on Twitter: "The 1km pit straight, where the cars reach over 300kph and maximum rev limit, gives a possibility for a double KERS release. Wind direction can often change at Barcelona due to its proximity to the sea and mountains. This can make gear ratio selection difficult particularly as there are a couple of bumps, which can cause the engine to hit the limiter."

Track temperatures are not quite as high as they were yesterday - 28C for now rather than the 44C we peaked at in FP2 - but they are still climbing. Good news for the likes of Lotus which performs well in hot conditions

The large leaderboard tower at the end of the pit lane spells out 'Bienvenido' as we hit five minutes to go before going blank in preparation for some times

Ravin has emailed in talking about tyres: "The tyre compounds have made strategy more important making things more interesting and mixing up the field."

And then Marco asked: "Do you think the teams could opt for a 3 or 4 stop strategy tomorrow given the difference in times between the two compounds?"

I certainly think we'll see more four-stop strategies Marco. The soft tyre will only be good for shorter stints in the heat - especially because they will need to be used in qualifying too due to the lack of pace on the hard - so a lot of pit stops look likely

The light goes green and Kobayashi is first out on to the track

Flo-viz paint on the rear wing of the Red Bull - we're still seeing lots of new parts being evaluated by the teams

Installation laps going on with only Button, Hamilton and Hulkenberg yet to go out on track

Alonso takes the time during his installation lap to wave to the crowd

Ashik emails in: "What do you think about Ferrari after their upgrades? Do u think they are more competitive than the previous races?"

I'd say they are more competitive yes, but how much more is tough to say. Alonso downplayed expectations on Friday and despite being encouraged he did the same yesterday. Some other team members, however, believe Ferrari have made more progress than they are letting on

Hamilton is the last man to complete an installation lap and he's got the track to himself. Higher noses on both McLarens again

Chris in sunny Perth emails in to ask: "With Lotus a real possibility of another podium this time out - what if they win? Have we ever had five different winners in the first first races, drivers and teams?"

Well I've tipped Raikkonen to win and Lotus does look strong this weekend so it could well happen, but you'll probably be surprised to know that it has happened before. In 1983 the first five races - in order - were won by Piquet (Brabham), Watson (McLaren), Prost (Renault), Tambay (Ferrari) and Rosberg (Williams)

Charles Pic had the track to himself for a bit before he's joined by Raikkonen and Petrov

Just to give you an indication of the difference in pace of some of the teams, Raikkonen's first sector was 1.3s quicker than Pic's

But things are not all rosy for Lotus - Grosjean has stopped on the outside of turn ten - on part of the unused track - and the engine is off. On the radio the team tells him that the car lost fuel pressure

So that's the end of Grosjean's session after just two laps. It also stopped anyone setting a representative lap time while his car was being cleared

Rosberg and Ricciardo have now done so to be the top two. The fastest time is a 1:25.158

Raikkonen completes a 1:25.362 to go second fastest

Everybody is running on the harder compound

Perez goes comfortably quickest with a 1:24.554. That's on hards and already almost as quick as Alonso went on hards in FP1

Bit of a backlog at the chicane as drivers look for a bit of space to start a clear lap. Hamilton runs wide at turn three

Kartik asks: "Can we see Grosjean in Fp3 again or only in Qualifying?"

Only in qualifying I'm afraid, the problem is not one that will be quickly fixed and he's just referenced using "the other car" in qualifying

Ash emails in: "Are you expecting another Vettel vs Raikkonen spectacle for the win during the race tomorrow? I'm eagerly hoping so. Who has caught your eye thus far, where do Mclaren fit into things in terms of pace this weekend?"

I can't say that's what I'm expecting Ash, mainly because McLaren look very competitive and will be in the mix. If anything I think we're more likely to see a battle between McLaren and Lotus with Red Bull still a slight unknown

Maldonado has improved in second place to within 0.017s of Perez, while Hamilton is third on a 1:24.907

Samuel asks on email: "I am a die hard Ferrari Fan for 2 decades now. Will it be worthwhile now to watch qualifying session today, with their new upgrades coming in?"

It certainly will, Samuel, and make sure you're following with us too! Alonso said he hopes to be able to make Q3 more comfortably, but wouldn't predict how high Ferrari could get

Button locks up in to turn ten under braking as Hamilton improves to a 1:24.778. Button is 1.3s off the pace right now

Alonso now goes third with a 1:24.730

We're still awaiting soft tyre runs - I think Rosberg has just gone out on a set

Vettel improves his best time to a 1:24.628 to go just ahead of Alonso in to third place

Rosberg is indeed on soft tyres, but his first sector is not the fastest of the day yet. His second is another personal best but not the quickest we've seen

The final sector is much better, however. Fastest of the day and he goes top with a 1:24.070 to improve by around 0.9s

Massa complains of low grip levels over the radio

Button is still not happy at McLaren: "Awful rear end, traction is very poor"

A standard issue at McLaren, though. Hamilton's team radio: ""The car feels quite good today. What stopped me going faster was sliding at the rear, the rear tyres feel weak." It turns out those tyres had been used previously, however

Vergne goes quickest on softs on a 1:23.833

Perez then returns to top spot on a 1:23.742 on soft tyres

An update on Lotus: it has managed to get Grosjean's car back to the garage so if it can get it fixed he could theoretically go back out. If it was an obvious, simple issue that caused the fuel pressure to drop then we may well see a few late laps but I'm not holding my breath

Schumacher catches a big slide in turn nine on his soft-tyre lap. He lost a lot of time as a result and is a second slower than Perez. I get the impression the Mercedes cars have been running a bit more fuel though

Mike emails in: "Practice 3 - What's going on with Red Bull? Are they sandbagging? I would expect Mark to be closer to Seb at this track."

Seeing as Webber was still gathering data at the start of this session I believe Red Bull is quietly confident. Webber warned yesterday as well not to read too much in to the headline times - if you can't get the tyres switched on immediately you won't set a fast time but the car may still be very strong on race pace

Grosjean's got his helmet on in the Lotus garage. Perhaps I should have been holding my breath...

Rosberg does a 1m29.2s on a long run on soft tyres

Karthikeyan pits at the end of his 17th lap. His car was vibrating which could be due to a flat spot but he obviously needs to get as much track time as possible having only completed one full lap in the whole of Friday

Vettel with a 1m24.9s on the hard tyre - he's not put the softs on yet but Alonso has just gone out on the option tyre

Told you track temperatures would rise - we're now up to 42C

Both McLarens putting some soft tyres on, while Perez is now on a long run

Alonso goes second on the soft tyres - 0.065s slower than Perez

Button and Schumacher now on softs. Button should be on a low fuel run while Schumacher is on high fuel. Perez matching Rosberg's high-fuel pace, so Sauber looks pretty strong

Raikkonen goes fourth with a 1:23.936 on the soft tyre

Button is fast through sector one but loses time behind traffic in the final two sectors and goes fourth

Hamilton set the fastest first two sectors but came across Raikkonen and an HRT in the chicane and his lap was blown

Kobayashi now with the fastest middle sector...

And Kobayashi goes fastest with a 1:23.350

Maldonado then goes even quicker on softs with a 1:23.336. Webber's soft-tyre lap time was a 1:23.578 for third

I don't think we'll see many improvements as Glock appears to have a puncture and has parked his car on the exit of the pit lane

Then the track is clear again and Vettel goes quickest with a 1:23.168

The chequered flag is out and it looks like Sauber and Williams could be factors in qualifying later

Vettel is still pushing despite having taken the chequered flag. Obviously trying to see when the tyres will go off and attacking his pit box for a practice stop

A strange set of times today because plenty of teams were unable to set representative times. Button in eighth, Raikkonen in ninth and Hamilton in 16th all had their best laps ruined, while Grosjean was unable to set a time after his fuel pressure problem

I suspect it will be a very busy McLaren garage, however, as Button continues to struggle with his car on hard tyres. Still certainly contenders for pole position this afternoon, but at what cost tomorrow?

Make sure you join us for qualifying in two hours, it's shaping up to be a hugely tense session with Red Bull, McLaren, Lotus, Sauber and Williams all having shown impressive pace. Add in the unknowns at Mercedes and Ferrari and you can't afford to miss it! See you then.