A robber who repeatedly beat a teenage passenger in the head and face before stealing his iPod and mobile phone has been jailed for 32 months.

Thomas Songhurst, 21, was sentenced at Southwark Crown Court today after admitting robbing the 17-year-old on a train travelling between Mitcham Junction and Hackbridge on May 4, last year.

Police identified Songhurst from CCTV stills taken from the train's CCTV cameras.

However, police are still keen to trace two other youths pictured on board the train.

PC Gary Bellinger, of British Transport Police’s robbery squad, said: “This was a brutal and callous attack on a teenager who had absolutely no chance of defending himself.

“I hope the 32-month prison sentence handed down to Songhurst shows just how seriously these sort of offences are treated by investigators and the courts."

The victim, who was left needing hospital treatment after the incident, sought help from a woman in a separate carriage who helped him to call police.

He was left with cuts to his eyes and bruising to his face and head.

PC Bellinger added that police were still keen to speak to the other youths filmed.

“I am also appealing for anyone who recognises the two youths pictured in the CCTV images to contact police,” he added.

Anyone who recognises the two youths in the CCTV images should call British Transport Police on 0800 405040.