Formula 1 supremo Bernie Ecclestone has heaped further pressure on Australian Grand Prix organisers to make their event a night race - by dropping the firmest hint yet that he will not renew its contract if the start time does not move.
While Melbourne organisers have resisted moves to shift the Albert Park event into a night event - because of cost and environmental factors - Ecclestone has not given up his crusade for the start time to shift from its current 5pm slot.
Speaking to The Age newspaper, Ecclestone said: "We have a contract which we will respect - so up until 2015 we are in good shape. After then, we really don't know.
"If we were to have a divorce from our friends in Melbourne we would probably be walking away from Australia. Because I can't see how Adelaide could make it happen, or anywhere else, if Melbourne can't. The race itself, from our point of view, is probably the least viable of all the races we have."
Despite his threat, and his insistence that other races are ready to step into the breach if Australia's deal is not renewed, Ecclestone said he would rather a deal could be reached to keep the event on the calendar.
"We have other races ready to take the place of Australia - which we don't want to happen," he said. "But it would be wrong of me to have to report to our board, 'Terribly sorry about this but we have to walk away from wherever to retain Australia'."
Ecclestone's threats against the Australian Grand Prix are nothing new, and 12 months ago he was involved in a public war of words with Melbourne's Lord Mayor Robert Doyle over the future of the event.