A 41-year-old man was threatened with a knife during a robbery in Fishermead.
Police are now appealing for witnesses to the incident which occurred in an alleyway near the Gurnards Avenue roundabout, Fishermead, at 4.25pm on December 19.
The victim and a friend were walking from the city centre towards Porthleven Place when a man approached them from outside the hairdressers and asked to speak to the victim alone in an alley.
The victim followed and was then approached by three other men. One offender threatened the victim with a knife whilst the two other searched him.
The four male offenders then walked off in the direction of Gurnards Avenue.
Anyone with information should contact DC Wendy Cissell from Milton Keynes police station via the Thames Valley Police Enquiry Centre on 101.