Thames Valley Police is appealing for witnesses following a robbery in Campbell Park.
The incident occurred at approximately 8.30pm on Friday (July 21) about half way between the cricket pitch and the exit of Campbell Park which leads to Xscape.
A man was approached by around five men on bikes. One of the offenders got off his bike, approached the victim and grabbed him by his shirt and demanded he hand over his phone. The victim was then punched in the head and fell to the floor, causing bruising to the eye and ear.
A Samsung mobile phone and black leather wallet were stolen.
The first offender is a black man, about 5ft 4ins, between the age of 17 and 20-years-old, with black hair shaved around the sides with an afro on top. He was wearing a grey hoody, tracksuit bottoms and a black bandana covering the lower face. He was cycling a blue and white BMX bike.
The second offender is a black man, around 6ft tall, wearing a black hooded top with a black mask featuring a white skull.
The other three males were black and around 17 and 20-years-old.
Investigating officer, Police Constable Thomas Pillar, of the Investigation Hub, based at Milton Keynes, said: "We are appealing any witnesses who may have been in the area at the time of the incident or may have witnessed the incident.
"Anyone who recognises the description of the males should contact the Thames Valley Police enquiry centre on 101."