It’s a hugely symbolic week for the Pole, who always said that he would only return to the F1 paddock as a driver.

Having turned down opportunities to visit grands prix, that’s exactly what he did when he arrived at the circuit on Monday, having opted to skip the race weekend itself. On Tuesday morning he was already on the pit wall, watching the progress of Renault test driver Nicholas Latifi.

So what is the point of the exercise, and what exactly is he hoping to achieve?

The answer is simple. By the end of Wednesday Kubica wants to be regarded not just by Renault, but by the whole F1 paddock, as a credible contender for a future race seat.

It's not about proving to himself, or even the Renault engineers who have long admired him, that he can do it – his two test outings in the 2012 Lotus-Renault E20 have already done that. Now it's just a question of perception.

And as ever, that's an important factor. When the subject of Kubica came up recently one senior F1 team person said he thought that the Pole would have no chance of being able to return, that he was deluding himself, and was in for a big disappointment – and that Renault shouldn't have gone along with encouraging his dreams of a return.

Kubica has to put an end to such negative beliefs once and for all, and Wednesday is his chance to do that.

The growing momentum behind his push for an F1 return is surely one of the biggest stories the sport has seen in recent times. His CV may include just a single pole position and one grand prix win achieved with BMW Sauber, but he was always regarded as one of the best of his generation.

Just a month older than Lewis Hamilton, he rose through the karting and single-seater ranks alongside both the Briton and current world champion Nico Rosberg, frequently sharing podiums with them.

"Robert's one of the quickest drivers I've ever raced against," said Hamilton when asked for his thoughts in Hungary. "He's one of the best drivers I've driven against. If he was still racing today he'd been in contention for a world title, if he'd not won one.

"Just raw, natural talent, which I think as a sport it's a shame we don't have here with us – because there's not a lot that comes through. Not a lot of great, great drivers come through. You have some that are much better than the rest, but still not the greatest, and then you have real special drivers like him."

That's an extraordinary endorsement by any standards, and it shows just how much respect Kubica's peers have for him. Hamilton also neatly sums up one important consideration: if you are a team boss, there is always a shortage of super talented drivers.

It's not easy to sign up a Hamilton, Sebastian Vettel, Max Verstappen, Fernando Alonso or Daniel Ricciardo. If Kubica can put himself back into that elite group, his presence will add an interesting new dynamic to the driver market.

He is already in the frame at Renault. That wasn't the case before the initial invitation to test the E20, when expectations were being firmly played down, and it was seen as a favour to an old friend of the team.

"The fact of the matter is simple," said team boss Cyril Abiteboul after that first run. "There is at Enstone a group of people composed of Bob Bell, Nick Chester, Alan Permane, all these people have known Robert as a driver, have worked with him, and over the years – including when Robert was completely outside of the radar – they have maintained contact with him.

"And that's something that they always discussed, what if, as a dream he was capable of driving again in this type of circumstance? We had this circumstance, we had this opportunity.

"This was a one-off. It's part of a process of recovery for Robert, where he's going to assess his limits – his physical limits, and also maybe his mental limits, what he has the appetite for going through also in terms of challenges, in terms of difficulties, in terms of risk, for himself for his image.

"He's also done F2, GP3, LMP2, Formula E, so he's done a number things, and this was also part of the programme. But I don't want to create an obligation on Renault or Robert that there is a next step."

That final point was an important one. While happy to help him out, Renault didn't want to raise Kubica's hopes too much, only for him to see them dashed.

However, his performance in Valencia changed all that. It quickly emerged that he had done a stunning job, overcoming all the challenges he had to face, and outpacing regular tester Sergey Sirotkin.

A second outing in Paul Ricard with the old car saw him make further progress. That and his performance in the simulator – Renault organised time for him at Red Bull – led to the chance to try the current car. Fortunately, a slot was available at the Hungary test.

This week's running is essential to his comeback hopes. The 2017 cars are the fastest and most challenging F1 has had in years, so it's vital that he can both discover what they are like to drive, and demonstrate that the extra cornering forces and so on are not an issue.

And even more importantly, he can do it in public, in full view of the other teams, and with nine other cars on the track. It's useful too that with its relentless series of turns, and inevitable hot conditions, the Hungaroring is a challenging venue.

It's worth recalling that Nico Hulkenberg qualified seventh, and best of the rest, last Saturday. In doing so, the German benchmarked the Renault as the fourth quickest car at the Hungaroring.

The drivers who in theory should thus be quicker than Kubica on Wednesday are Sebastian Vettel/Kimi Raikkonen (Ferrari), George Russell (Mercedes) and Pierre Gasly (Red Bull). Teams operate different programmes in testing, of course, and not all of those guys will necessarily have a chance to make full-on qualifying runs.

You can be pretty sure that Kubica will be allowed to go for an ultimate laptime – not just for show but because he has to continue to sample all race weekend circumstances. It will be fascinating to see where he will be in the order at the end of the day relative to some of the top prospects from the current generation.

The Renault engineers are already confident that the experience will be a breeze for him. They've already seen enough in the E20 – and he wouldn't have got to this stage had they not been convinced that he is a credible candidate for a race seat.

This will just be the final proof, for Renault's top management, the team's sponsors, and the world at large. One question has already been answered, for on Monday he passed the FIA's strict cockpit exit test.

Kubica's possible rivals

So who is he competing against for a 2018 Renault seat, given that Jolyon Palmer's chances of surviving appear to be slim at best?

Fernando Alonso has long been on the manufacturer's wishlist, but it's obviously a question of whether the Spaniard thinks the team can be a genuine contender next year and be a real step forward from McLaren – not to mention his financial requirements.

The name of Carlos Sainz continues to be mentioned, but that would inevitably involve some compensation for Red Bull, while F2 racer and Renault protege Oliver Rowland made it clear at the weekend that he harbours hopes of getting the job.

One outside bet could be the mercurial Charles Leclerc: he's Ferrari's man at the moment, of course, but the Monegasque can't be ruled out of contention for a Renault seat.

And that leaves Kubica.

It's by no means a given that a brilliant and convincing performance on Wednesday will propel him into a race seat, but it will put him firmly in the frame. And as noted earlier, he will also potentially be on the radar for everyone else too, and that could open up some interesting possibilities.

For the past year he's been managed by the well-connected Alessandro Bravi, who also looks after Stoffel Vandoorne.

The Italian lawyer previously worked with Nicolas Todt's management company, and was thus involved in the careers of the likes of Felipe Massa, Pastor Maldonado and the late Jules Bianchi. He knows the right people at all the teams, and he knows what boxes his driver will have to tick.

As Hamilton said, Kubica is a rare talent. If you were a team boss, would you sign someone of the calibre of a Hamilton or Alonso or Verstasppen with a physical limitation that they have proved that they can overcome – and who will by handy co-incidence also bring huge PR value with them?

Or would you take chance on an unproven F2 graduate? While championship leader Leclerc is highly regarded, there's a widespread perception that this year's field does not have strength in depth.

If you put the pieces together, Kubica starts to become a serious prospect. And consider too the levels of motivation, and sheer force of will, that have brought him this far, and which have helped to make him a more mature and rounded individual than he was back in 2011. He would be a huge asset to any team.

The rally accident robbed Kubica of what, as Hamilton suggests, would have by now been a stellar career. And now, against all the odds, a second chance is within his grasp. Let's hope that he is able to take it.