A 22-year-old man was arrested on suspicion of an assault on two teenagers and a policeman at Wimbledon station on Saturday night.
Police were called to the scene just before 11pm and arrested the man on suspicion of being drunk and disorderly, sexual assault, wounding and assaulting a policeman.
The teenage couple, both 16-years-old, were on a night out when the alleged assault took place.
The suspect has been bailed until February 25 while police investigate.
Anyone who witnessed the incident should contact British Transport Police on 0800 405040, quoting crime reference number 594, January 25 2014.
- Neighbours pay tribute to south London pensioner who was fifth person to die after Westminster terror attack
- 'It's important to stand together': Ahmadiyya Muslims show support for victims of Westminster terror attack
- Drug that reverses ageing may be available to buy in three years
- Cat killer: Decapitated cat found in Wimbledon
- You're wheelie stupid: 'Idiot' kids getting high off fumes from burning bins