A man knocked a robber to the floor with a punch after the criminal brandished a knife.
The victim was walking towards Trinity Avenue along St Georges Avenue, Northampton, at around 3pm on Monday, June 13, when he was approached by two men.
One asked him if he wanted to buy drugs before pulling out a knife from the right-hand pocket of his tracksuit jacket.
At that point the victim punched the robber, knocking him to the floor. The second man helped the first man up and they both made off in the direction of Kettering Road.
Nothing was stolen and the victim did not suffer any injuries.
The robber was white, in his late teens to early twenties, with a very pale complexion. He was about 5ft 7ins to 5ft 8ins and skinny. He was wearing a blue Adidas tracksuit jacket, matching bottoms and a baseball cap.
The second man was about 5ft 7ins to 5ft 8ins, in his late teens to early twenties and with brown, cropped hair. He was wearing a light-coloured hoody, dark trousers and a baseball cap.
Anyone with information can contact Northamptonshire police on 101. Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111.