An incident in which a man was caught on camera appearing to carry out a homophobic rant at a Tube passenger is being investigated by police.
British Transport Police were alerted after a clip was put online and later published by LBC radio. The rant seems to have begun after the passenger was confronted for hurling abuse at a drag queen on the London Underground.
BTP described the scene as "completely unacceptable behaviour", while Karl Turner, Labour's shadow justice minister, tweeted: "We need zero tolerance on religious, sexually or racially motivated attacks whether verbal or physical."
A BTP spokesman said: "We have been made aware of a video on social media which appears to show a man making homophobic comments and threats of violence towards passengers on a London Tube train.
"Officers are viewing the footage and making inquiries to establish the full circumstances of the incident and when and where it took place.
"This is completely unacceptable behaviour."
They are asking anyone who recognises the man involved to contact BTP on 0800 405040, or text 61016, quoting reference 146 of 2/1/2016.