It happened close to the shops.
A man held a Stanley knife to the 39-year-old victims neck whilst a woman went through his things in the early hours yesterday.
The offenders made off with cash, a bank card and tobacco.
Investigating officer, Detective Constable Rebecca Nightingale, based at Oxford police station said: "I am appealing to anyone who may have witnessed this assault to come forward.
"If anybody has any mobile phone footage or dash-cam footage of the incident, please get in touch.
"In particular, I would especially like to hear from a taxi driver who is believed to of witnessed the incident and members of the public who were in the vicinity.
"Anyone with information can call 101 or make a report online quoting reference ‘43190154488’.