"There's something going on" behind closed doors at Mercedes.

That is the suspicion of former F1 driver and UK television pundit Karun Chandhok, referring to Lewis Hamilton's protracted negotiations that culminated in a mere one-year contract for 2021.

Chandhok's colleague Martin Brundle said he met the seven time world champion recently and found Hamilton's pre-season mood to be "grumpy".

"There's something going on there that they won't tell us," Indian former driver Chandhok told the Finnish news agency STT.

"It is not common for the world champion to be the last driver in the entire team to make a contract, and it's not common for the best team in Formula 1 to have a vacancy until January."

However, some have compared the situation to Ayrton Senna in 1993, when the F1 legend flirted with a move to Indycar as he argued with McLaren over money and openly coveted the Williams seat.

"I don't think this situation is similar, because this time there is no clear explanation," Chandhok said. body check tags ::