Flash mob organisers are being urged to refrain from holding such events at railway stations by the British Transport Police.
It follows the closure of Liverpool Street station about two weeks ago when about 12,000 people took part in a Facebook-driven flash mob event.
Commuters were affected during rush-hour when overhead and underground trains did not stop at the station.
The BTP said it aims to find out where flash mobs are being held in advance.
BTP Deputy Chief Constable Andy Trotter said: "When you get thousands of commuters trying to go home at a very busy station in the middle of rush-hour and then joined by thousands of people who want to dance that can then be a problem."
Referring to the flash mob event held in London on 13 February at Liverpool Street, he said: "Passengers could not go about their business and as a result people were angry and clearly that is not a good recipe for a busy evening in London."
He said flash mobsters are not considerate to commuters.
Flash mobs are spontaneous parties set up on the internet or via text messaging.
Participants are given details of the meeting point and are when to disperse, often leaving onlookers confused.
BBC London research discovered there are at least 500 Facebook groups for flash mob.
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