The assault happened as he was walking along a footpath with a friend behind Silver Green close to the Fairstead Estate.

He was then approached by an unknown man who carried out the assault.

The offender has been described as a white male, aged between 27 and 35. He had short blond hair and was wearing a light blue vest top and white trousers.

Police are appealing for any witnesses to the incident, which happened last Tuesday (6 October) at around 3.30pm, to come forward.

Contact PC 670 Emily Carter at King's Lynn Police Station on 101 with information that may assist officers with their investigation.