Media reports in the last days have suggested the Spaniard, whose five-year stint at Ferrari appears definitely over, has now decided to re-join McLaren to spearhead the team's new works Honda era.

Italy's Tuttosport said the contract is for two years with a total value of EUR 70 million.

On a visit this week to Mexico City's rejuvenating F1 venue for 2015, however, Alonso denied the reports.

"There is nothing new," he insisted. "I have decided nothing for next year - nothing is definite yet.

"With Ferrari I am seeing what is the best decision for next year, whether I continue or not, but I will try to choose what is best for my future.

"I have something in my head, but every week for the past two months there have been these rumours, always with a different team.

"I respect Ferrari greatly," Alonso said. "It is a team that I love. For Ferrari it has been a difficult year, and for me it has been five difficult years."

Would it be McLaren or sabbatical?

On the face of it, it seems Alonso's only choice is McLaren or a sabbatical, leaving Jenson Button increasingly nervous about the likely end of his F1 career.

In his latest interview with Hermes, former McLaren driver Mika Hakkinen agrees: "Jenson's behaviour lately reflects a certain loss of confidence.

"I think when you are striving for success in the long-term, your behaviour looks different."

Between Brazil and Abu Dhabi

McLaren acknowledges that it has put Button and Kevin Magnussen in an awkward position as the Alonso talks drag on.

Team boss Eric Boullier may now be losing patience.

"We want to have Fernando's decision between Brazil and Abu Dhabi," the Frenchman is quoted as declaring clearly to the German newspaper Bild.

"We have had good conversations with him, he would fit well with us and he has signalled that he wants the job.

"However, we want a long-term solution - three years - not just a contract for one."

Alonso, Vettel and Hamilton

Honda is making no secret that it wants a driver of Alonso's top calibre for 2015. The BBC has reported Alonso is on the verge of agreeing a two-year contract plus a further option for 2017.

"We cannot comment on the drivers as it is a subject for McLaren and Honda," said the Japanese marque's F1 chief Yasuhisa Arai, according to Spain's Marca.

"But Alonso, Vettel and Hamilton are very strong drivers and all the teams want them. Any one of them has a chance of being in the team in 2015," Arai added.

The big favourite is clearly Alonso.

"There are simply moments in your career when you know that you have to change teams," McLaren legend Emerson Fittipaldi said. "Fernando has arrived at such a moment."