Thames Valley Police are appealing for witnesses following an assault in Oxford.
At around 7.20pm on Thursday (18/7), the victim, a man in his fifties, was involved in an altercation with another man in Cowley Road, Oxford.
The victim was taken to hospital for treatment.
At around 10.30pm, a member of the public found the victim collapsed in London Road, opposite Bury Knowle Park.
The victim was then taken to hospital for treatment where he remains.
Investigating officer, Detective Inspector Mike Roddy, of the Thames Valley Police Major Crime Unit, said: “We are appealing for anyone who may have witnessed this incident to please come forward.
“This was a vicious assault that has left the victim with serious head injuries.
“We would also like anyone who saw the victim in London Road, to please get in touch.
“Further to this, if any motorists or cyclists were in the local areas around the time of the assault or when the victim collapsed, please check any dash-cam footage in case it may have captured something that could assist with this investigation.
“I would like to reassure the public that we believe this is an isolated incident, and officers have made an arrest.”
“If anyone has any information, no matter how small, that could help with our enquiries, please call 101, quoting reference number 429 (19/7) or make a report online.”