A 22-year-old man was robbed on a section of the redway between Beanhill and Netherfield last week.
At 12pm on Thursday the victim was walking along the redway when he felt a sharp pain in his back and felt someone grab for his mobile phone.
He turned round and saw a man who threatened him and demanded his Cubot mobile phone.
The victim handed over his phone and the offender ran off in the direction of Ashland or Netherfield.
He did not sustain any injuries.
The offender is between 6ft and 6ft 2ins, of a stocky but muscular build with a square jaw and dark stubble.
He was wearing a dark blue hooded top and light grey jogging bottoms. He carried a light green laptop bag over his shoulder.
Police are appealing for witnesses who may have seen the offender in the area or anyone acting suspiciously.
Anyone with information should contact Det Con Susan Russell on 101.
If you don’t want to speak directly to the police, you can contact Crimestoppers anonymously on 0800 555 111.
No personal details are taken, information is not traced or recorded and you will not go to court.