Toro Rosso technical director James Key described the work done by Honda over the winter as "encouraging" after the junior Red Bull completed the most laps of any team during the first Formula 1 test.

Brendon Hartley and Pierre Gasly turned a combined 322 laps over the effectively three days of running after Wednesday was washed out, with the latter completing a single day best of 147 tours of the Circuit de Barcelona-Catalunya on Thursday.

It wasn't just the strong reliability either, with Key suggesting the performance figures from Honda mean they are now in a position to challenge the three manufacturers ahead of them.

"We had a good feel for where the Renault was last year and at least from the numbers you see, which you always have to treat carefully because they are from different dynos etcetera, it's not so far off," he told Sky Sports.

"Not nearly as far as was being suggested last year actually. It was probably pretty close to Renault towards the end of the season and obviously they've made steps for this year and that's encouraging."

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The respected British designer does admit their new Japanese partner is not quite on the same level yet as their former supplier, though doesn't think it will take too long. 

"The good thing about what we saw from Honda last year is despite all the difficulties they had over the first half of the season they still had the capacity to go and develop the power unit and it definitely was better by the end of the year," Key stated.

"That trend appears to have continued into this year and, as long as that trend continues, there's no reason why they can't genuinely be challenging Renault by mid-season or the end of season. That's what we'd like."

Toro Rosso's showing in Barcelona has immediately drawn some to wonder if McLaren ditched Honda at just the wrong time, but Key believes the working relationship the Italian team has is much different and is working better.

"[We are] trying to give Honda the freedom they need," he said. "Fundamentally we wanted to give them the opportunity they needed to get on with the job. I think they appreciated that."

Sebastian Vettel was pleased with his first day behind the wheel of the new Ferrari SF71H after topping both the lap time and lap count standings in Barcelona on Tuesday.

The German four-time world champion completed 98 laps with a 'best of the test' so far of 1:19.673s which just put him ahead of the Mercedes of Valtteri Bottas.

However, understanding that the lap times are not particularly important at this stage, it was the distance covered which gave Vettel the most optimism.

"We managed to cover almost a hundred laps without encountering any reliability problems," he proclaimed. "That’s what we are concentrating on at the moment, with the search for performance coming later."

It was testing last year which offered the first indication that the Scuderia had closed the gap to Mercedes so, as a result, many wondered how the 30-year-old's impression of his new car compared to his last.

"The fact it’s been much colder than last year and also that the track has been completely resurfaced means it’s impossible to make any comparisons," Vettel responded disappointingly.

"For now, we are concentrating on ourselves, without looking at what the others are doing."

Lewis Hamilton set the quickest time on the final day on the first Formula 1 test as Mercedes offered a glimpse of their potential in Barcelona.

After the snow and rain of Wednesday, sunshine and more temperate conditions welcomed the teams although the day was still split between wet running in the morning and a dry afternoon.

The world champion was only in his W09 for the afternoon but completed 69 laps with an impressive best of 1:19.333s on the Medium compound tyres, less than two-tenths slower of Sebastian Vettel's fastest time over the four days on Soft compound Pirellis on Tuesday.

The pace of teammate Valtteri Bottas in the morning was perhaps more notably as he held a substantial advantage over the field in the wet before the track dried enough for a single run on slicks to end his stint.

McLaren had a strong Thursday also, as Stoffel Vandoorne completed a lot of work on the new Hypersoft tyre, setting the second-best time and managing 110 laps in total before handing over to Fernando Alonso.

The Spaniard would add 51 more laps to the British team's total in the final four hours with the fifth best time at the end.

Sebastian Vettel was third for Ferrari, turning a second-best 120 laps on the day, the honour of the most distance covered belonged to Toro Rosso and Honda again as Pierre Gasly managed 147 laps.

Kevin Magnussen was within a second of Hamilton's pace for Haas in fourth, following a short run on the Supersoft rubber in the afternoon as Carlos Sainz maintained Renault's solid first week with 60 laps and P6.

Both Williams drivers got the chance to get more mileage under their belt with Sergey Sirotkin driving in the wet morning, therefore ending bottom of the timesheets, and Lance Stroll in the afternoon finishing seventh.

Sergio Perez made his first appearance for Force India this week, after the day's running was lost on Wednesday, with the Mexican completing 65 laps in eighth.

Max Verstappen was late to the action, opting not to run in the wet and would cause a red flag in the afternoon after going off at Turn 12 in a scruffy day which saw the Red Bull only ninth.

Gasly was 10th with Nico Hulkenberg 11th having also had the worst of the conditions in the morning for Renault.

The two Sauber drivers, Charles Leclerc and Marcus Ericsson completed 138 laps between them but were the slowest of those who ran in the dry. 

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Pierre Gasly vented his frustration at the Halo after revealing it tore his race suit as he climbed in and out of his Toro Rosso car in testing.

The debate over the controversial cockpit device has rumbled ever since it was first suggested with one of the main issues being the ability for a driver to escape a car quickly after an accident.

For 2018, the FIA's minimum exit time has been doubled from five to ten seconds and as Gasly explained, the use of Halo for aerodynamic purposes has only complicated the situation.

“You need to be a lot backwards to slide in the car, it’s actually quite weird," after running for the first time on Tuesday.

“And with all the winglets you have on the Halo, you cannot really pull to get out and touch it. It’s quite weird conditions, but nothing really important. I just prefer the old cars.”

On the damage done to his race suit, the former GP2 champion added: “Already, it’s only the first day and I have many holes on the back.

“I think my suit is already broken, so we’ll have to ask for many suits from Alpine Stars this year.

“I don’t like it, it’s a big mess to get in the car and get out,” Gasly concluded.

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This week it was expected that any unexpected consequences from the Halo would be discovered.

When in the car, however, drivers are reporting that Halo is not impacting their vision and, after a few laps, they even forget it is actually there.

Daniel Ricciardo also played down concerns about seeing the start lights after doing a test on Monday, though Carlos Sainz has admitted it does make it harder to assess rain intensity.

McLaren racing director Eric Boullier has slammed the two teams who blocked a motion to extend this week's test in Barcelona as "selfish".

After dealing with frigid temperatures all week, the situation only got worse on Wednesday as snow and rain washed out Day 3 with only five of the ten cars opting to leave the pits at all.

With time already tight to be ready for the first race in Melbourne later this month, it was suggested to add an additional day of running with the weather set to improve in the coming days but ultimately the bid was unsuccessful.

"To change testing dates, we would have required unanimity," Boullier told Sky Sports. "It appears that two teams did not want to change the date yesterday."

Those two teams are believed to be Ferrari and Sauber, both of whom have filming days booked at the Circuit de Barcelona-Catalunya over the weekend.

On Wednesday, McLaren, with Fernando Alonso, was the only team to surpass ten laps and post a lap time so bad were the conditions but Boullier was left frustrated by the week as a whole.

"It's obviously wasted money," he claimed. "We spent the money to be here and the track is booked for two weeks anyway.

"We had the possibility to move that day to another one later. We know the forecast is better on Sunday or Monday.

"We need these eight days to offer a decent show on-track for race one, covering reliability issues and everything we need to cover," he added. "That's purely wasted money on selfish interests."

Many have used this week's experience to argue F1 must now consider returning to the Middle East for testing next year, where conditions in February are more representative of the majority of races.

"The cost is one of the elements of going to Bahrain, it’s not easy, but also the logistics," said Haas team principal Guenther Steiner in response. "You guys have no idea how much stuff is coming here every day for the car. It’s brutal.

"If it’s in Bahrain you need to get prepared, it’s the same for everybody. But the next thing is, some teams would put a jet on every night to go back and forward."

Fernando Alonso was the only man to set a lap time as Day 3 of the first Formula 1 test was washed out by snow and rain.

A winter wonderland greeted the teams in Barcelona on Wednesday as heavy snow fell overnight and for much of the morning meaning the start was delayed by four hours.

Even when the track did go green, however, the snow had simply turned to rain leaving the circuit sodden throughout the day.

As a result, only five cars ventured out at all, all day with three just doing basic installation laps. Daniel Ricciardo did attempt a timed lap only to end up in the gravel before returning to the safe sanctuary of the garage.

Local hero Alonso was not to be deterred though, managing 11 laps and completing a 2:18.545s, almost a minute off the best time seen over the previous two days.

Despite suggestions of extending the test to Friday, those teams that had arranged filming days were not willing to give them up.

Therefore, a full day of running has been lost in what was already a very short amount of on-track action before the teams head to Australia for the first Grand Prix.

Williams reserve driver Robert Kubica has revealed his frustration at the media's constant questions regarding his physical limitations.

The Pole did have his right arm partially amputated following the horrific injuries he sustained in the rally crash seven years ago which ended his first stint in Formula 1 but has been trying to overcome them since returning to the cockpit with Renault initially last summer.

Some believe lingering concerns could have played a role in Williams choosing Sergey Sirotkin for a 2018 race seat, as well his test performance and additional sponsorship money, but the 33-year-old thinks there has been too much focus.

"I have always been comfortable, it was only media talks that I was not comfortable," he said after running on Tuesday and Wednesday in Barcelona.

"If I keep changing things you will keep saying I have limitations [but] if I can jump in the car and do the job I think that's fair enough, of course I have my limitations but I never hide them."

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Kubica did admit, however, that perhaps he had been too open about discussing his physical condition.

"The problem is I was too honest with everybody and they kept asking questions, I think we should stop it," he stated.

"We have things to concentrate on. I’m living a good experience, I’m enjoying my role. I’m happy to give positive messages, not always the same story after many years."

Sebastian Vettel repeated Daniel Ricciardo's achievement from Monday by putting Ferrari top of both the timings and the lap count on the second day of testing in Barcelona.

On a day when very low temperatures in Catalonia again impacted run plans, the German, getting his first taste of the SF71H, completing 100 laps with a best of 1:19.673s on the Soft compound tyres.

That came during a stint of qualifying-style runs in the afternoon, which saw the four-time world champion go for a quick time every other lap. Vettel would also cause a brief red flag after spinning at Turn 2 on an earlier run.

With teams largely restricted to aero runs in the morning due to the weather it was around the lunch break, which was cancelled to allow an extra hour or running in the 'heat' of the day, before any serious lap times were set.

It also meant Mercedes kept Valtteri Bottas in the car throughout the day, instead of switching to Lewis Hamilton in the afternoon, and the Finn would post the second-best time in the W09, the only other driver to dip below the 1:20 mark.

After Fernando Alonso's moment on Day 1, Stoffel Vandoorne again as relatively high on the timesheet in third, albeit using the new Hypersoft tyre, but also among the lowest in distance covered with only 37 laps in the morning as the Belgian didn't emerge at all in the afternoon.

On his first day in the RB14, Max Verstappen lost some of the morning to a leak in the fuel system in his Red Bull but made up a solid amount in the afternoon with a solid 67 laps and the fourth best time.

Carlos Sainz was sixth completing the trio of Renault-powered cars with Pierre Gasly continuing Toro Rosso and Honda's good start to testing with 82 laps and the sixth fastest time some 1.7 seconds slower than Vettel.

Williams would split their day between Sergey Sirotkin and Robert Kubica and it was the Pole who was three-tenths faster in the better conditions in seventh with the Russian race driver eighth, both combining for a team best of 99 laps on Tuesday.

Esteban Ocon was ninth in the Force India ahead of F2 champion Charles Leclerc as the Monegasque made his first public appearance behind the wheel of a Sauber.

He would end the day just 0.007s clear of Kevin Magnussen who rounded out the timings in the Haas.

Max Verstappen had a positive first impression of his new Red Bull RB14 after testing for the first time in Barcelona on Tuesday.

The Dutchman was hampered by a leak in the fuel system which cost him much of what was a quiet morning anyway, but made up for lost time in the afternoon ending with 67 laps on the day, one more than the usual Spanish Grand Prix race distance.

Offering his initial opinion on the car, the 20-year-old believes it is very much a step ahead of where the Red Bull was at this stage this year.

"It was a positive day, so I am pretty satisfied," he stated. "It is still early and you always want to fine-tune the balance, but the first impression is very positive, more so than last year."

Also Read:

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• Ricciardo confident of greater Red Bull title bid

Having committed to the Milton Keynes outfit until 2020 late last year, Verstappen is eager to see his trust repaid with a car capable of fighting for the title. But he wasn't getting ahead of himself by making any predictions.

"I don’t know if the car is good for victories. I only drove this car once and I think nobody has shown anything yet," he said.

"However, I do know when a car is performing well or not. And this car is performing well. We have no problems, and that is a big difference with last year."

Red Bull team principal Christian Horner claims the political relationship between Ferrari and Mercedes means Formula 1's top two teams are effectively "working as one".

The two manufacturers have made no secret of their aligned agendas with Mercedes motorsport boss Toto Wolff admitting the German carmaker would consider joining Ferrari in quitting the sport if they disagreed with the direction taken by current owners Liberty Media.

"Mercedes and Ferrari are working as one team these days," Horner said at the first test in Barcelona. "For the last couple of years there has been a very tight relationship between them, they even broadcast each other's launches and things like that these days."

In recent months the moves by Liberty, who want to take away the power of the manufacturers and create a level the playing field financially and competitively, have resulted in the split between the manufacturers and the independent teams such as McLaren and Red Bull.

"We are focused on going racing, things that we can control, there are new owners in F1 in Liberty and they have to decide what they want F1 to look like moving forwards," the Briton continued, laying out their position.

"I'm sure they will lay out their roadmap and plan during the course of this season and we will go from there, but of course, there is going to be a lot of posturing and positioning and you can see that has already started in certain quarters."

One area Mercedes and Red Bull do seem to agree, however, is on rejecting thoughts of a breakaway championship created by Ferrari, as suggested by ex-F1 CEO Bernie Ecclestone over the weekend.

Horner described his comments as nothing but bluster with talks to agree a new Concorde Agreement upcoming and Wolff described it as a "hand grenade".

"We are committed to F1," the Austrian ressuringly added. "This is our joint-platform and we all benefit if it is running well.

"We are critical on some of the things because we want F1 to do well but we invest a lot in this platform. It's a major global sport that has grown over the years and we feel responsible.

"[We are] giving the management of F1 and the FIA the utmost support to solve the problems, to make it great and improve the show. This must be our clear number one priority."