Police have issued more information about a teenager who pulled a knife on a 13-year-old boy and punched him in the face and head.

A group of teenagers allegedly followed the victim off the train at Ewell West station on the afternoon of Saturday, January 24.

One of them caught up with the teenager and attacked him on Chessington Road at the junction with Meadowview Road.

Epsom and Ewell Safer Neighbourhood Team released a CCTV image on Facebook on Friday of three young people they were looking to speak to about the attack.

But a police press release issued today only referred to one suspect - suggesting that the two others have been identified and eliminated from the inquiry - although police have yet to confirm this.

Confusingly, the safer neighbourhood team said yesterday: "Thank you for all of your comments and interest regarding the incident relating to the 13-year-old boy who was assaulted. The persons shown in the CCTV images have been identified."

Today's police statement said the victim boarded the train in Guildford with some friends travelling towards Raynes Park.

A police spokeswoman said no arrests have been made, adding: "The teenager was attacked by only one suspect."

The attacker was described by police as about 15 and 5ft 9in. His hair was cut short on the sides and he had a brown Timberland bag.

He wore a gold stud in his left ear, red and black Nike Air Max trainers, a black Adidas jacket and True Religion blue jeans with a red stitching.

PC Jack Poynter, who is investigating the attack, said: "This was a nasty and traumatic assault on a boy that occurred in broad daylight.

"Not only did he receive injuries to both his head and face, he was left badly shaken and distressed by the ordeal.

"I urge anyone who may have seen, heard on since gained any information in relation to this incident to contact us as a matter of urgency."

Anyone with information should call police on 101, quoting reference number 45150006751. Alternatively call Crimestoppers on 0800 555 111.