[A] aged 15 was arrested on Tuesday, 22 November for robbery and subsequently bailed to return to police on a date in early January pending further enquiries.
Enquiries continue re a second suspect.
Officers in Wandsworth released CCTV footage of two people they needed to trace following the incident on Wednesday, 28 September.
At approximately 16:00hrs the victim was with his friend at a bus stop near the Londis store in Falcon Road, Battersea.
He was approached by two youths who robbed him of his money and assaulted him.
The victim then boarded the 319 bus and sat downstairs as the suspects went upstairs. He got off the bus and contacted police.