A male suspect tried to grab a bag from a 38-year-old male victim. Despite the victim falling on his hands and knees in the struggle and being punched twice in the face, he kept hold of the bag, which contained a laptop computer.
Police are keen to speak to two men sitting on a bench near the junction at the time of the incident.
The suspect is described as a black man, aged 20-23. He was wearing a black T-shirt with white writing on it and a black jacket.
If you have any information contact Sutton Police station on 101. Alternatively, contact Crimestoppers anonymously on 0800 555 111