Sebastian Vettel has flatly denied that he has signed to race with Ferrari or in 2014, or come to any agreement or understanding with the Italian team that could see him leave his current berth at Red Bull.

"Yes, I can deny," when asked point-blank by Sky Sports F1 reporter Ted Kravitz if he was able to give an unequivocal answer to the rumours that have persisted through the summer about the world champion's future. "I don't have any agreement or obligation."

Team principal Christian Horner has also consistently dismissed rumours that Vettel was looking to exit Red Bull after one more season in 2013:

"Absolutely, he will be here in 2014, no doubt about it," Horner told reporters on Friday. "Sebastian Vettel, without a shadow of doubt, will be part of the Red Bull Racing team in 2014."

Also this weekend, team advisor Dr Helmut Marko told reporters on Thursday that Red Bull had a "bullet-proof" contract with Vettel extending into 2014

However, Marko has also previously revealed that the team's contract with Vettel contains various performance clauses which could conceivably allow the German driver to break the contact and depart early if he chose to.

Speculation that Ferrari might have a secret deal with Vettel was rekindled after the Italian team opted to re-sign Felipe Massa for another season in 2013 despite a largely disappointing year for the Brazilian. Many pundits speculated that this was a "stop-gap" solution designed to keep the seat open in 2014 for the arrival of Vettel.

But comments from Ferrari president Luca di Montezemolo about not wanting to have Vettel and Fernando Alonso at logger-heads within the same team garage poured a measure of cold water on the persistent speculation.

"2014 is still to come but I don't want to have two roosters in the same henhouse, rather two drivers who race for Ferrari and not for themselves," di Montezemolo said earlier this month. "I don't want problems and rivalries, which we didn't have between Schumacher and Irvine, between Schumacher and Barrichello, between Alonso and Massa or Massa and Schumi or Massa and Raikkonen."

With Alonso's position at Maranello looking very secure after a highly-praised performance in a less-than-perfect F2012 car which has kept him in the title battle, that seems to rule out any move by the team for Vettel's services in the short- to medium-term.

Although as anyone will tell you, anything can happen in F1 and usually does. No one's saying never and the speculation will doubtless continue for months to come.