Kimi Raikkonen's new Ferrari deal was understood to be a precursor to Vettel agreeing what may well be just a single-year extension to his stay at Maranello.

That trigger would confirm Valtteri Bottas' position at Mercedes too, with all the big teams' focus really on what Max Verstappen will do longer term – from 2019 and beyond – at Red Bull.

The lockdown at the front would lead to few opportunities for change elsewhere, with Robert Kubica likely to be the only dark horse for a potential seat at Renault as the French manufacturer eyes up a range of drivers including Fernando Alonso and Esteban Ocon.

But as the F1 paddock regrouped at Spa-Francorchamps, a sensational possibility was being gossiped about in the paddock, as whispers – first reported from the highly respected Auto Motor Und Sport – suggested that Williams was on the chase for Fernando Alonso's signature.

Alonso has been weighing up his future for some time, and has long talked about his determination to stay in F1 only if he has competitive machinery.

But hopes of landing title-winning machinery immediately seem remote - with Ferrari, Mercedes and Red Bull not particularly interested in having him on board.

Indeed, the choice for him seemed to be clear: stick it out with McLaren after giving his all over the last three years, or quit and go race some place else.

While the Spaniard has no doubts that the team has the infrastructure and budget to give him what he needs for his F1 future, it is the engine that has become the main sticking point.

And with hopes of a McLaren deal for Ferrari and Mercedes customer engines having long faded, the options on the table right now are of a slim chance of Renault power units or a pray that gains consultant Ilmor has found giving Honda a step forward he so wants.

Speaking about the decision that McLaren may have to make – have faith in Honda one last time or push for Renault – Alonso gave a cryptic response. "I don't think there is a tough choice," he said.

But did he mean that it was obvious what McLaren had to do, or simply that, with Renault reluctant to expand to a fourth supply, there was nothing for McLaren to choose? He did not elaborate.

Pushed on whether the engine decision would be decisive for him regarding his 2018 decision, Alonso said: "Not really. It's the performance what will dictate what I will do and the conditions of next year."

But one way that Alonso could get himself a guarantee of the best engine in F1 would be to jump ship from McLaren and join Williams – which has a deal for customer Mercedes power units.

From Williams' side, such a move would be a sensational coup and welcomed with open arms.

It would lift the team's reputation massively, give it a big performance boost and would be a sponsors' dream – especially for title sponsor Martini which would enjoy a big lift in global brand exposure.

The real question is whether or not such a move is attractive enough for Alonso. For Williams does not appear to be a team that is capable of delivering Alonso in the short term the third world championship he craves so much, nor potentially even wins.

You have to go back more than five years – to the 2012 Spanish Grand Prix – for Williams' last victory when Pastor Maldonado stunned the paddock and beat Alonso himself across the line.

This year Williams is fifth in the constructors' championship, a whopping 60 points off Force India ahead – and few are linking its Silverstone rival with a bid to lure Alonso away.

Yet the hard results do not tell the true story of the progress that Williams has made over the last 12 months – nor even of how different even this season could have been.

Let's not forget that were it not for a failed shock absorber, Felipe Massa could have gone on to a famous victory in Baku – which would have transformed the outfit in the eyes of the world.

There have been changes behind the scenes too following the arrival of Paddy Lowe, who has begun making the changes to the infrastructure that he feels are needed to make the step up the grid.

Such change takes time, but at least in Lowe Williams has a man who knows exactly what resources and commitment are needed to win championships following his successful spell at Mercedes.

And potential for resources is certainly something Williams is not short of right now, with Lance Stroll's father Lawrence more than open to digging deep into his pocket to help fast-track progress in a bid to make the team better – which in turn will have good returns for his son.

Alonso will be aware too that its strong form this year – with Massa often fighting for the best-of-the-rest tag behind Mercedes, Ferrari and Red Bull – has come despite him having gone into last winter with retirement firmly on his mind.

Alonso knows the edge he had on Massa when they were together at Ferrari, and it would not take much to work out what he could be doing with that car if you take a couple of tenths of a second off what the Brazilian has been doing.

Equally it wouldn't be lost on Alonso though that there is a big gap currently between Williams and the top three teams – a gap that even his brilliant driving would not be able to overcome if the team does not make progress. Is it a gulf too big to overcome in just a single season?

But with the F1 paddock in its holding pattern for 2019 – when the driver market will really explode and Alonso will definitely want to be a free agent – is there any more to lose with a single year gamble that could deliver some good results.

Few doubt that a few years ago – especially in 2014 – Alonso would have been able to win races for Williams.

The real question now is does he believe such a scenario could return for next year, or is he still better off sticking it out at McLaren and having faith that it makes the right call on engines?

That's something only he can decide.