A man followed a woman off the Tube and assaulted her at Kilburn Underground station.
Detectives investigating the alleged assault have released an image of a man who may have information that could help them.
Police say the incident took place at around 9.25pm on Thursday, June 22 on a train between Finchley Road and Kilburn.
The man began acting aggressively towards the victim before she got off the train at Kilburn.
He then assaulted her before running away, British Transport Police said.
Anyone who recognises the man pictured is asked to contact BTP by texting 61016.
Alternatively, you can call 0800 40 50 40 quoting reference 721-220623.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here