Audi chief executive Rupert Stadler keeps F1 speculation alive, admitting it is an option.

Whilst talk linking the Volkswagen owned company with F1 has been going for as long as anyone can remember, speculation intensified when parent company VW Group chairman Ferdinand Piech sensationally resigned last month.

Piech, grandson of Ferdinand Porsche, had always ruled out F1 claiming that he could not see what would be gained by entering the sport. He also had an intense dislike of Bernie Ecclestone and made no secret of it.

Already enjoying a strong motor sport presence with Audi and Porsche in WEC, Bentley and Lamborghini in GT Racing and VW itself in WRC, F3 and Rallycross, F1 would seem the obvious next move for the VW Group and last year Audi further fuelled speculation when it hired former Ferrari team boss Stefano Domenicali and Williams and BMW engineer Jorg Zander.

Speaking to Auto Express' Mike Rutherford, Audi chief executive Rupert Stadler further fuelled the speculation.

"In life you must keep things open," he said. "We're already well stuffed with successful motorsport projects. But with F1, wait and see. It's an option for Audi. Not at this moment, perhaps. But it is still an option."

This of course, ties in with comments made by Red Bull motor sport advisor Helmut Marko at the weekend. "If we don't have a competitive engine in the near future, then either Audi is coming or we are out," he told BBC Sport.

Quick to deny that there have been formal talks, and also mindful of the upheaval within the VW Group, he added: "There are so many rumours. Officially there was no request or talks. The VW Group first has to sort out who will be the new chief of support, who will run the brand of VW, and when they have sorted all these things maybe then they can think about what they are doing in motorsport. I was on the phone but not to the people you think."