Lewis Hamilton's future remains up in the air as he continues to stall on a new contract with Mercedes.

The latest rumour doing the rounds regarding the world champion suggests that he could even be seen in red next season, racing alongside Sebastian Vettel.

No-one knows what is going through the British driver's mind, except Christian Horner, it seems, who hazarded a guess that money was at the centre of his dispute with his current team.

The 33-year-old may even leave F1 altogether, but he was happy to joke publicly with Vettel about them working with each other in the future at a press conference in Monte Carlo earlier this week.

Hamilton joked that the German would "veto" any such move, with Vettel in turn pointing out that he was happy working alongside Kimi Raikkonen.

Nevertheless, the question has again been put to the Ferrari star of whether he would be happy for Hamilton to replace Raikkonen and he reiterated what he had said about the Iceman.

"I prefer Kimi, to give you my honest answer," he told CNN.

"If you ask me if I'm afraid of [Hamilton] then no," added Vettel, jesting:

"He's not taller than me, I don't think he's heavier than me, so in boxing terms I'm not afraid.

"Politics or misunderstandings" 

"In the end you have to be prepared to race whoever comes along, I don't know what is his plan in the future.

"But if I had to pick, I would pick Kimi, simply because there's no danger or threat of any politics or misunderstandings."

That last comment may be a reference to Hamilton's somewhat difficult reputation and it doesn't sound like Vettel is overly keen on bringing him to Ferrari, even if his presence would make them even more formidable.

Ultimately, all that is left to be done is for the face of Mercedes to make up his mind and announce his plans for next season and beyond.

Whether he'd be welcomed elsewhere will surely be something he'll have to take into account.

Would you like to see Hamilton join Ferrari? Have your say in the comments.