Jenson Button and Kevin Magnussen’s McLaren futures remain undecided after a board meeting failed to resolve the long-running saga of the team’s 2015 driver line-up.

McLaren are the only confirmed team on next season’s grid yet to announce their 2015 line-up – although Fernando Alonso is understood to have already signed up – and had put off final deliberations until this week at the earliest.

A decision on who occupies the second seat had finally been expected to be taken at a board meeting at the team's Woking base on Thursday, however the team confirmed that no agreement had been reached.

“Today's board meeting has now concluded, and no decision has been taken with regard to our 2015 driver line-up,” a McLaren spokesman said.

Jenson Button still doesn't know when he'll find out if he's part of McLaren's plans for next season. Jenson Button still doesn't know when he'll find out if he's part of McLaren's plans for next season.

The additional delay in the episode is bound to invite further suggestions that the Woking outfit are taking unnecessarily long to decide whether Button or Magnussen are best suited to partnering the returning Alonso in the first year of their new Honda era.

There have been suggestions that the big difference in wages earned by Button, a former world champion, compared with 22-year-old Magnussen was central to the discussion, however Sky Sports News HQ understands that while such financials are a consideration they are "not a decisive factor" in the ongoing deliberations.

It is understood that while McLaren's shareholders couldn't decide on what their best line-up is in Thursday's meeting, they are keen not let the situation drag on for much longer.

"There was a theory that they wanted to wait and see how much money Fernando Alonso might bring in to see if they can afford Jenson Button alongside him, who is paid considerably more than Kevin Magnussen is," SSNHQ's Craig Slater reported.

“But I understand that at this board meeting today, the significant board members genuinely could not decide on what their best line-up is. It was the big beasts in there today – Ron Dennis, Mansour Ojjeh and Sheikh Mohammed bin Essa Al Khalifa – and between the three of them they could not come to a definitive conclusion.

“It’s open-ended as to how long this will take but my understanding is this will not be allowed to drag on to the next board meeting in the New Year. So we’re looking at a period of days rather than weeks and what will happen is those three principals will confer informally over the phone in the meantime and come to some sort of realisation, I would guess in the next week or so.”

Despite their futures being up in the air, the two in-limbo drivers attended a McLaren sponsor event in Edinburgh earlier on Thursday with both men confirming they remained none the wiser as to their futures at the team.

“That is a question I still cannot answer, I don’t know when we will all find out,” Button told Sky Sports News HQ on Thursday when asked about his F1 future.

“I think for all of our sakes it is better sooner rather than later. I am here with Kevin as well and we have spent the last couple of days together and we’ve had some interesting conversations. Whatever way it goes it is better that we know sooner rather than later."

Speaking at the season finale in Abu Dhabi, McLaren chief executive Ron Dennis made clear that the belated decision on the line-up would be a collective one taken at the top level of the company.

"I've not made up my mind yet, but (the decision on the driver line-up) is not mine alone, and anyway, it wouldn't be appropriate. Any decision has to be supported by the shareholders and the board,” Dennis said last week.

"It's pretty understandable we're looking at two people, and there's a broader choice than Kevin and Jenson, but nevertheless whatever the decision, it won't be taken until (the board meeting)."

While neither driver stayed on in Abu Dhabi to test the interim McLaren-Honda last week, team chief Eric Boullier made clear the decision to run with Stoffel Vandoorne – a driver who has been more loosely linked to the second seat – was in no way linked to their driver plans for 2015.

Should McLaren's decision go against Button then it is likely to signal the end of the Briton's 15-year F1 career. The 2009 world champion has made clear he would only be interested in staying in the sport if he had a race-winning car, with a switch to the World Endurance Championship his likely next destination in such a scenario.

Magnussen, meanwhile, made his most recent appearance on social media on Monday to tweet a farewell message to his fitness trainer Antti Vierula, who is leaving the team after four years. Previously the Finn was trainer to Sergio Perez and Lewis Hamilton before teaming up with Magnussen ahead of the Dane's 2014 rookie campaign.

Check out our feature looking at five respective reasons to keep Button and Magnussen, while also have your say on McLaren's likely 2015 line-up in our website poll

How the 2015 grid is shaping up:

MERCEDES Lewis Hamilton and Nico Rosberg

RED BULL Daniel Ricciardo and Daniil Kvyat

FERRARI Sebastian Vettel and Kimi Raikkonen

WILLIAMS Valtteri Bottas and Felipe Massa

McLAREN TBC

FORCE INDIA Nico Hulkenberg and Sergio Perez

TORO ROSSO Max Verstappen and Carlos Sainz

LOTUS Romain Grosjean and Pastor Maldonado

SAUBER Marcus Ericsson and Felipe Nasr

MARUSSIA (ENTERED AS MANOR F1 TEAM) TBC

CATERHAM TBC