The incident happened on Bedhampton Way near the junction of Colemore Square between 8.30pm and 8.45pm on Friday 30 October.
The man was walking along Bedhampton Way when he was approached from behind by a man not known to him. The man was carrying a knife which he used to threaten the victim with, before assaulting him and taking his wallet.
The man has been described as:
- Aged between 18 and 20-years-old
- 5 feet 7 inches
- Slim build
- Wearing a black hooded top
- Black face mask
- The man was also described as speaking with a London accent.
The victim suffered a small cut to his neck and bruising to his face as a result of this incident.
Officers investigating would like to hear from anyone who was in the Bedhampton Way area around this time on a Friday night who saw anything. Specifically, if any drivers were passing through the area who have dash cam footage, or residents with private CCTV.
If you have any information that can help us, please call 101 and quote 44200421866.
Alternatively, you can call Crimestoppers on 0800 555 111 and leave information anonymously.