EPIC fundraiser Mark Allison was forced to stop for the day by a lack of light overnight as he neared the end of his run across Australia.
He set off on October 16 from Cottesloe Beach, near Perth, and has already covered more than 2,000 miles.
A spokeswoman for the Sir Bobby Robson Foundation said today: "He's also been told the other side of Macquarie Pass is misty and he can't risk running on dangerous roads in those conditions.
"His run will resume at first light in Australia - 5pm UK time - this means Mark will be running the day of his flight home. This run really is going down to the wire."
Earlier, Mr Allison's partner, Donna, said: "Still not totally clear on more detail for the finish. Mark has ran so so well today. I can tell he's in pain but it's a case of head down and get the job done.
"He could be running until midnight tonight, it's an hour by hour review at the moment. The likelihood is that he will finish around 9am-ish - again quite woolly - local time."
To donate to the two charities, visit virginmoneygiving.com/rungeordierun