The Japanese Grand Prix was barely over when McLaren's inner turmoil was exposed, as neither Jenson Button nor Fernando Alonso chose to confirm team boss Ron Dennis' pre-race assertion that both would "be in Melbourne next year, 100 per cent."

Alonso is one year into a three- year contract and Dennis indicated that Button's option will be taken up to give him a second year. But at the end of a weekend in which speculation has surrounded both drivers' futures and each was critical of Honda's lack of power, neither appeared willing to back up his confidence.

At noon, two hours before the start, Dennis gathered media together and said: "Jenson has a two-year contract.

"I told him - probably too late - that we have no intention of letting our option lapse. I told him on Thursday, probably I should have told him on Tuesday."

Team sources suggested Dennis had been unwell earlier in the week but he looked fit and well when he arrived in Suzuka from meetings with Honda in Tokyo.

Dennis also admitted that he had tried to beat his driver down on remuneration that had been agreed when Button's contract was renewed - with a pay cut - for 2015.

"I'm a businessman and I did explore that between him and I.

"But that's my job."

Sources within McLaren suggest the Button situation is complicated but the team need him more now than they did a year ago. This is because sponsor Diageo, the world's largest spirits conglomerate, is about to launch a new marketing initiative in 50 countries. It features Button and actor Jude Law. You have to be 25 to participate in such things, which would rule out McLaren's back-up youngsters Stoffel Vandoorne and Kevin Magnussen should Button and Alonso decide to decamp.

Reacting to Dennis' comments after the race, Button said: "It's still not public. You don't know the truth of the matter.

"It's not the time to share it because nothing is done."

Both he and Alonso were harsh in their criticism of Honda's engine after finishing 16th and 11th respectively. Button said he felt like "a sitting duck" and was concerned about the speed of cars overtaking him. Asked if he intends to stay, he added cryptically: "It's so tough because Fernando and I are used to fighting but we're not even fighting. It's like a samurai without his armour and sword."

Alonso began the weekend reacting to suggestions he is leaving by saying: "Definitely, I can tell you that I will not go anywhere else."

He ended it being rebuked by Dennis for suggesting his engine was like one from a GP2 car.

Dennis, walking the tightrope of wanting more competitive performance without sounding disrespectful to Honda's top brass, said he was unhappy with Alonso's comments and would speak privately with him.

"I'm not going to condone those sort of things. He is in the car, he is frustrated and his remarks to the technical staff were not a particularly constructive way to communicate with everybody."

Considering that McLaren recently stacked the media against Honda's engine man Yasuhisa Arai, after arming them with loaded questions at one of their regular Saturday evening "meet the team" gatherings, that seemed a bit rich.

Asked after the race whether he would be at McLaren next year, Alonso replied: "I don't know", before remembering the script and adding lamely: "I am sure we will win together but the matter is when."

Insiders suggest he will take a sabbatical. That could open the door for GP2 champion-elect Vandoorne, reckoned to be someone quite special by all who have been watching him this year, to join Button for a learning year in 2016 prior to an all-out title challenge with a returned Alonso in 2017. Assuming that Button stays of course.