Red Bull boss Christian Horner initially thought Daniel Ricciardo was "joking" when he called to say he would not be re-signing for 2019, according to the Daily Mail.

Last Friday, the story many have waited all year for was made as the Australian confirmed his plans for next season, with the Milton Keynes outfit announced his departure before Renault was revealed as his next destination.

The news has surprised many given Red Bull is part of the established top three on the grid while the works team for the French manufacturer is still in the process of rebuilding after buying the remains of the Lotus team at the end of 2015.

Concerns over the pending switch to Honda engines and perhaps unhappiness at the growing power of Max Verstappen within the team is what most are pointing to as the reasoning, while the man himself insists he wants a "fresh challenge".

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Even so, it is reported the news completely blind-sided Red Bull who had agreed to terms and even produced a video confirming Ricciardo's retention, perhaps explaining why Horner didn't believe the 29-year-old at first.

In typical Daily Mail fashion, the newspaper claims some within the team see his decision as Danny Ric "running away from Verstappen" as the Dutchman continues to improve.

Another incentive could be money too, with Renault reportedly paying £20m-a-year for his services, a figure some put at three-times that he was making at Red Bull.

Two-time Formula 1 world champion Mika Hakkinen claims he does see traits in both Sebastian Vettel and Lewis Hamilton which are comparable to his main rival Michael Schumacher.

For Vettel, much of his career has been about trying to emulate the success of his German idol with his move to Ferrari in 2015 largely driven on the motivation to follow in the footsteps of the record seven-time champion.

What the 'flying Finn' has also noticed are the several similarities between the approach of the 31-year-old and the man he fought in the late 1990's, early 2000's.

"I first think of Sebastian’s driving style as unique, but the similarities to Michael are there," Hakkinen told Speedweek.

"He always braked at the same point, always drove the same line, accelerated very sensitively, everything controlled.

"It’s a very good, clear, clean and aggressive driving style. Even over the kerbs, he always has the car under control."

As for Hamilton, he had the privilege of being the man to replace Schumacher at Mercedes when he hung up his helmet a second time in 2012 but for Hakkinen, there is a key difference between the two men.

"Lewis always tries to drive a bit more extreme. Very controlled, but he pushes the car more to the limit and risks much more," said the former McLaren driver.

"But it is not careless, he makes conscious decisions. If he does not go off track, a super lap comes from his effort. You can take that risk, but not always, otherwise you’ll spin sooner or later."

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The 49-year-old concluded by looking at the current state of F1 and was optimistic about the current situation.

"Formula 1 has not been as exciting for a long time now," he admitted. "Rosberg against Hamilton was anything but boring, but the number of fans was reduced by the duel within one team.

"Now Mercedes against Ferrari, plus the young talents like [Max] Verstappen – now it’s exciting."

Haas F1 team boss Guenther Steiner has suggested Formula 1 stewards are biased in their decisions towards the leading drivers on the grid.

With two aggressive racers in Romain Grosjean and Kevin Magnussen in their ranks, the Italian has admitted trips to the stewards' room are almost customary during Grand Prix weekends.

However, when considering how any subsequent penalty is applied, Steiner does think the smaller teams or lesser profile drivers pay a greater price for their errors.

“We are easy to pick on, I guess is what you’re saying?" he told Motorsport.com.

“Sometimes we don’t help ourselves to put ourselves in this position – if you didn’t need to go there you wouldn’t get the penalty but if there is a decision to be taken, I still think that who you are counts for what the outcome is. It should all be without a name.”

While conceding it was only a hunch and he has "no evidence" to back up his pretty bold claim, FIA race director Charlie Whiting didn't rule out some external factors influencing decisions.

“If a driver’s got nine points on his licence that shouldn’t influence the stewards’ decision,” he said.

“If they think they shouldn’t give him three because he’ll have to take a race off, that shouldn’t come into it, but whether it plays a sub-conscious part I don’t know.”

Last week's two-day test following the Hungarian Grand Prix may not have meant much to many on the grid, for Robert Kubica though it marked an important milestone in his road back to Formula 1.

It was exactly a year ago that the Pole made his first public appearance in a current generation car with Renault at the Hungaroring, as the French manufacturer weighed him up for a possible seat for this season.

That path would eventually close, but Williams would become his next one and result in his current position as reserve and development driver for the Grove-based team.

Back on track in Budapest last Wednesday, Kubica looked back on the progress he has made over the past 12 months.

"After 12 months I can say everything is easier!" he said. "One year ago everything was new for me, especially with the new generation of F1, and now everything is more familiar, easier and I'm more confident. So all good."

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His first official role back in the sport hasn't been easy with Williams struggling at the back of the grid with a flawed car that has created far more headaches than it has happy memories.

"It was all ok. We did have a bit of a mixed program with some data collection for next year, and trying to understand how we can make the car work better for next year's car," Kubica explained.

"But we did do a few runs with a current specification car as well. So the feeling was good."

Part of his program also saw him become one of the first drivers to test the new 2019-spec front wing which is designed to allow drivers to follow much more closely.

"It's wider and you can feel that," he said in assessment. "But it's too early to have a good opinion about it.

"It was a test for our aerodynamic engineers so that they can collect data about how the air flow is affected and so on."

Doctors taking care of triple Formula 1 world champion Niki Lauda have given a positive update on his recovery after undergoing a lung transplant.

The Austrian, who now sits as non-executive chairman at Mercedes, was notably absent from the final two races before the summer break after falling ill on holiday from what was believed to be a severe case of summer flu.

After flying home, it was later diagnosed as a serious lung disease resulting in the successful transplant which took place late last week.

“Everything is currently going very well and we are very satisfied,” confirmed the head of thoracic surgery at the Vienna hospital where Lauda was treated.

“Considering the not very easy circumstances we are very, very happy with the developments."

The news also came around the 42nd anniversary of Niki's infamous crash at the Nurburgring in 1976 which left him with severe burns and lung damage after inhaling the smoke and other fumes from his fiery Ferrari.

Unsurprisingly, the question was asked if there was a link.

“One can absolutely assume that lung transplantation is not a late consequence of the fire accident,” he said.

Writing on Twitter before signing off for the summer break, Mercedes motorsport boss Toto Wolff paid tribute to the 69-year-old.

"The world knows Niki as an F1 legend with incredible power and resilience, for all of us at Mercedes he is our chairman, our mentor and our friend," he said.

"We have missed him by our side in Hockenheim and Hungary, and can’t wait to have him back with us.

"The recovery he faces is not a race, but I’m sure he will soon be telling every nurse and doctor that he has had enough of hospital.

"We wish him a safe and speedy recovery – in that order – and send all our positive energy to him and his family.

"I miss you my friend," he added.

Doctors believe it could around a month before Lauda is back at full health.

Daniel Ricciardo will be leaving Red Bull after five seasons to join Renault in 2019, it has been announced on Friday.

The Australian's future has been one of the biggest questions throughout this year with rumours linking him to Ferrari and then claims he was being offered big money by McLaren, potentially to replace Fernando Alonso.

With options at other top teams closing, as Mercedes re-signed their drivers and the Scuderia consider their highly-rated youngster Charles Leclerc, it appeared almost certain that the 29-year-old would be staying put for at least two more years.

After testing in Hungary this week, however, Ricciardo put in his notice at the Milton Keynes outfit.

“We fully respect Daniel’s decision to leave Aston Martin Red Bull Racing and we wish him all the best in his future,” said team boss Christian Horner.

“We would like to thank him for his dedication and the role he has played since joining the team in 2014, the highlights, of course, being the seven wins and the 29 podiums he has achieved so far with us.”

Speculations had suggested Renault was the most likely destination and that has now been confirmed with the French manufacturer announcing the 'Honey Badger' will be replacing Carlos Sainz, with the Spaniard likely heading in the opposite direction.

"It was probably one of the most difficult decisions to take in my career so far but I thought that it was time for me to take on a fresh and new challenge," Ricciardo said.

"I realise that there is a lot ahead in order to allow Renault to reach their target of competing at the highest level but I have been impressed by their progression in only two years, and I know that each time Renault has been in the sport they eventually won.

"I hope to be able to help them in this journey and contribute on and off track."

Renault Sport managing director Cyril Abiteboul added: “Daniel’s signing underscores our determination to accelerate our progress towards the forefront of the sport and it is also a recognition of the work accomplished over the past two and a half seasons.

"Daniel’s undoubted talent and charisma are a huge bonus and statement for the team. We will have to repay his faith in us by delivering the best car possible. We welcome him to our growing team in 2019 with a great deal of pride, but also humility.”

Red Bull's plan to promote Carlos Sainz into the seat vacated by Daniel Ricciardo for 2019 could be facing a big hurdle, Max Verstappen.

The Spaniard has always been considered to be first in line for a switch to Milton Keynes when the opportunity arose, however, it is also well-known that the Dutchman and the Spaniard have history from their time together at Toro Rosso.

It wasn't until Verstappen switched to Red Bull part-way through 2016 that Sainz emerged from the shadow of the 20-year-old and started producing the performances which arguably made him too good for the junior team and attracted the interest of Renault, leading to the loan deal for this season.

Faced with the prospect of teaming up again though, according to Spanish newspaper Marca, Max is believed to be pulling his weight inside the team and potentially pushing for Pierre Gasly to get the nod over the 23-year-old.

That would appear to be true based on a tweet later sent by Sky Sports commentator and F1 veteran Martin Brundle who gave his full support to 'Chili'.

"If Carlos Sainz doesn’t get a strong drive in F1 next year it will be a travesty, annoy me intensely, and reflect badly on F1," he claimed.

Potentially ready to bring the second generation driver in from the cold is McLaren with speculation continuing to link him to Woking and forming an all-Spanish line-up with hero and mentor Fernando Alonso.

While former racer Pedro de la Rosa has warned against it, after his comments about losing out on Ricciardo, CEO Zak Brown was also asked about the possibility.

“We think Carlos is an excellent race driver,” he said.

“Of course Carlos is potentially on the market, we don’t know his exact situation at Renault and Red Bull, but he’s certainly someone that as you go down the shortlist of drivers you’d consider putting in a race car.

“If he was free, and if we had a seat, he would certainly be high up on the consideration set.”

Ferrari's new CEO Louis Camilleri has offered a mixed first statement on his view regarding the talks with Liberty Media over the future of Formula 1.

Camilleri was drafted in last week by company chairman John Elkann after the sudden death of his predecessor Sergio Marchionne following complications after shoulder surgery.

Given the hard-line approach Marchionne had, threatening to pull the Scuderia out of F1 if he didn't agree with the approach taken, many were waiting with baited breath to see if his replacement would be any different.

"There are ongoing talks with Liberty Media," Camilleri reportedly told Italy's La Gazzetta dello Sport. "I think there has been progress on the technical side, but less on the budget cap and governance.

"I'm not sure about new ideas, the goal is to divide the cake as it is. We do not talk about how to increase it. I am sure I can bring my contribution."

That would suggest little has changed in terms of Ferrari's position but there was no comment as to his position on the company's future in the sport, however.

Given Camilleri and team boss Maurizio Arrivabene are both former executives at Phillip Morris it is also thought his arrival won't see too many changes to the current Maranello operation.

CEO Zak Brown believes McLaren's lack of competitiveness in the period through Formula 1's triple-header of races likely cost them the chance to sign Daniel Ricciardo, who will move to Renault for 2019.

The Australian was linked to the British team around the French Grand Prix last month, with Red Bull advisor Helmut Marko revealing "big money" was being offered for what many assumed to be the seat held by Fernando Alonso.

However, at the time it coincided with several retirements and poor pace as McLaren often sat second-to-last in the pecking order just as they were in conversations with the soon-to-be ex-Red Bull man.

"I think it was probably pretty close between us and Renault," Brown told RACER. “Had we been running more competitively I think that would have increased our odds."

The McLaren chief never tried to hide his interest in signing the 29-year-old and revealed just how far their efforts to attract him went.

“We had a couple of meetings and we are big fans of Daniel,” he said. “I think he’s a great guy, I think he’s a great race car driver.

"How close we came to getting him, I think only Daniel knows the answer to that question," he added. "Ultimately Daniel would be best to tell you how close."

Brown also wasn't as surprised as many when the news was confirmed last Friday, suggesting he felt a "strong desire" from Ricciardo to leave Red Bull.

His decision to join Renault is still being considered bold by many, however, and former driver at Enstone, Jolyon Palmer, does have some concerns.

"To be honest, it's a backwards move for Ricciardo," the Briton told BBC Radio 5 Live. "They're a team that's on the up but they are currently behind, there's no two ways about it."

The ex-GP2 champion does think there is one factor which was heavily motivating the seven-time race winner's wish for a new challenge.

"At Red Bull, I felt - and he probably felt - that he was just starting to slide into Verstappen's shadow," Palmer claimed. "And that's a dangerous place to be."

"He's come into a team [at Renault] that will be really excited to have him and they'll be really pinning a lot of hopes on him to move forwards.

"It's a little bit of the whole dynamic within the team which is better for him at Renault even if they're technically a little bit behind."

Former Formula 1 driver Pedro de la Rosa is warning Carlos Sainz not to join McLaren in 2019 and race alongside fellow Spaniard Fernando Alonso.

The current Renault driver is facing something of an uncertain future with Esteban Ocon linked to his seat and Daniel Ricciardo set to remain at Red Bull, with the second generation driver first in line for a promotion to the Milton Keynes outfit.

With Stoffel Vandoorne's poor record of results this season, the chance to create a Spanish 'dream team' has been touted, particularly given the long relationship Sainz and Alonso have had with the 23-year-old idolising the double world champion.

"I think it would be better if they were not together," De la Rosa was quoted by F1i.com.

"Being Fernando's teammate is very difficult, so I prefer that someone other than Carlos suffers.

"I would prefer if Carlos gathers two or three more years of experience and then face a beast like Fernando."

The long-time McLaren test driver, who also raced with the team on nine occasions, does think Renault, where Sainz is currently on loan, would make a mistake in letting him go.

On the rumours over his future, however, Sainz is remaining coy.

"I cannot comment on it," he said at a press conference last week.

"Nothing changes until my future is decided by Red Bull or if Ricciardo doesn't sign a deal etc. My future is still uncertain and I'm not linked with any other team yet."

Alonso's own future with McLaren is yet to be decided also, with the 37-year-old claiming he will think about it "on the beach".