Robert Kubica's father says the Pole is still in the running to be named Williams' second driver for 2018.

Multiple sources reported this week that although the Pole was the recent favourite, the strongly Russian-backed Sergey Sirotkin ultimately won the day with better pace in Abu Dhabi and a much bigger sponsorship purse.

However, the latest word from Williams is that the British team is in fact "not planning any statement in the coming days".

That is despite the fact that Russian sources were reporting this week that the Sirotkin deal could be made official on Friday.

Now, Kubica's father Artur Kubica says the Polish camp is still pushing hard for the seat.

"We're still fighting to get Robert into Williams," he told Sportowe Fakty.

"We hope that it is a good decision for us. And if it is not made before Christmas, it means that at least the people at Williams are taking time to think.

"We are taking steps to convince them to believe in Robert," Artur Kubica added.

He didn't say what those 'steps' may be, but admitted that amid the Sirotkin speculation, it is sponsorship dollars that sometimes talks the loudest.

The rumours are that Sirotkin, potentially enjoying even the backing of Russian president Vladimir Putin, is promising over EUR 15 million in backing, while Kubica can bring just 8 million.

"Of course it is about what the driver will bring to the team. Sometimes, skills, experience and the potential of the driver are decisive, at others only the money counts," admitted Kubica senior.

Sportowe Fakty also claimed Kubica attended Williams' Grove factory on Thursday.

(GMM)