A probe has been launched after two young girls were upskirted while walking through Tottenham Court Road station.
Police are appealing for information after a man pointed his phone camera upwards to film the young girls at around 2.15pm on Tuesday July 14.
The incident was noticed by a fellow passenger who confronted the man and followed the suspect until he left the busy tube station, which is served by the Central, Northern and Elizabeth lines.
Officers have shared a picture of a man they would like to speak to in relation to the offence.
The photo shows a middle-aged man sat on a London Underground train wearing a dark blue top and glasses.
Anyone who recognises him should contact British Transport Police on 61016, or call 0800 40 50 40 using the reference 321 of 14 July.
Information can also be reported anonymously to Crimestoppers.