A British man is fighting for his life after being found lying in the middle of a street in Sydney with a fractured skull and broken ribs.
The parents of Daniel Moore, 21, are flying to Australia to be at his bedside as police attempt to discover what happened to him.
Officers found him in the road suffering from severe injuries, including internal bleeding, in the northern suburb of Manly early on Sunday morning.
He was taken to Sydney's Royal North Shore Hospital, where his condition was described as critical.
New South Wales Police are appealing for the driver of a taxi seen in the area at the time to contact them. It is believed that the taxi stopped shortly before the incident and then continued down the road where Mr Moore was found.
A New South Wales Police spokesman said: "Police would now like to speak to the driver of a taxi who is believed to possibly be one of the last people to have seen Mr Moore.
"Police are hoping the driver of the taxi may be able to assist with inquiries and the circumstances surrounding the incident."
Mr Moore, from Marske-by-the-Sea, Redcar, Cleveland, had been living in Manly, whose beaches and bars make it popular with surfers and backpackers.
It is believed he had been in Australia for about two years and may have been saving up to visit the Indonesian island of Bali, the Sydney Morning Herald reported.
Inspector Bob Bell, from Manly police, told the paper: "It's a bit of a mystery. We're following a certain line of inquiry. He's the one bloke who can throw light on the whole thing... we haven't been able to speak to him because of his condition."