Thames Valley Police is appealing for witnesses after a robbery in Hodge Lea on Wednesday.
At about 6pm, a 28-year-old man was walking through the underpass between the V5 Great Monks Street and H2 Millers Way, with his mobile phone in his hand.
He was approached by five men, one of whom demanded his phone. The victim handed over his white iPhone 4S, which had an orange Superdry cover and the offenders ran off towards Hodge Lea.
The men are all white and in their late teens or early twenties. The man who demanded the victims phone is white, wearing a white baseball cap with a tick on it, a white Adidas hooded top, and dark trousers. He spoke with a local accent. The other men were dressed in similar clothing.
Any witnesses can call police on 101 or Crimestoppers, anonymously on 0800 555 111.