Police are investigating footage that appears to show a group of men brazenly smoking on a London Underground train.
The video, posted to YouTube with the title "Polish 'patriots' in London" - written in Polish - shows a large number of young men on the southbound Northern line service.
As the doors close at Belsize Park station in north London, the group of around 10 passengers can be seen passing around what appears to be a cigarette before some of them stand up and begin loudly chanting the Polish national anthem.
Towards the end of the clip, one of the men seems to discard a cigarette stub on the floor before stamping it out.
A British Transport Police (BTP) spokesman said: “We are aware of a video, appearing to show a group of men smoking on a London Underground train.
“Officers are currently analysing the video and trying to establish when it was recorded."
He added: “No smoking signs are clearly displayed on all Tube trains and anyone caught flouting the ban will be dealt with robustly.”
Anyone with information is asked to call British Transport Police on 0800 40 50 40 quoting 182 of 01/09/2015.
