On Tuesday, 19 April, shortly after 4pm, a 16-year-old girl boarded a route 222 bus in Bell Road, Hounslow.
She climbed to the top deck and took a seat.
A male, described as 5ft 5in tall, of chubby build, and wearing a dark coloured baseball cap and a mustard coloured T-shirt boarded and sat next to her.
Around 15 minutes later, as the girl was about to leave the bus, the male sexually assaulted her.
If you recognise the man in this photo or have any information that could help this investigation, please get in touch.
