LONDON, England (CNN) -- Thousands of dancers jammed a major London train station in a Facebook-driven "flashmob" mimicking an advertisement for a phone company.

And the event last Friday evening was so successful that another is planned for next Friday in Trafalgar Square in central London. Plus, a group has been set up to organize another one at Liverpool Street Station a week later.

Videos posted on the social-networking site showed Liverpool Street Station completely filled with people, counting down the seconds until the clock showed 7 p.m., then dancing to music on their mp3 players as the hour struck.

The sheer scale of the event came as a complete surprise to the organizer, a 22-year-old Facebook user who identified himself only as Crazzy Eve.

"I was watching TV and the T-Mobile advertisement came up and I thought, hm, let's get my friends down to Liverpool Street and do a little dance," he told CNN by phone. He posted the event on Facebook and invited his friends, who invited their friends, he said, and so on until thousands of people had been told of the plan.

"At a quarter to seven people just flocked into the station like someone opened a plughole and the water went out," he said. "They just kept coming in like sheep. As it grew and grew, I just thought, 'This is going to be huge.'" iReport.com: Were you there? Send your photos and video

His main memory of the event is "the volume of people -- you couldn't see the floor," he said.

He left after 15 minutes -- the scheduled ending time -- for fear of the police, he said, adding that he had deleted his name from the event Web site and refused to identify himself to CNN for the same reason.

"The entire main concourse was packed full of people dancing, cheering and screaming," said CNN's Simon Hooper, who was passing through the station on his way home.

"There were camera flashes going off constantly. There were also loads of people crammed around the edge of the upper level of the station, looking down at the scene below.

"There were a lot of bemused commuters wandering around the edges, trying to get to their trains but nobody seemed to mind too much. Everyone seemed pretty good humored," he said. "I think a lot of people who pass through Liverpool Street regularly are getting used to this sort of thing."

British Transport Police also described it as "mainly a good humored event," adding "No arrests were made and no crimes were reported."

Police did not have an immediate estimate of the crowd size, but more than 14,000 people joined the Facebook group "Liverpool Street Station Silent Dance."

"It was both good cause we all stuck like a group didn't stop dancing inside and outside but bad cause of the people who could get anywhere but hey I love it WE MADE HISTORY RIGHT THERE!!" one Facebook user said on the event's Web site.

"Yeah I agree, there wasn't any bad feelings there. Everybody just had a good time, apart from my friend being groped by some guy, but you'll always get one," another wrote.

The T-Mobile commercial which inspired the event shows several hundred people dancing in the station. The dancing in the advertisement appears to be spontaneous but was actually choreographed. It was filmed January 15 and has been widely broadcast since then.

The success of the event has prompted Crazzy Eve to call for another silent dance at Trafalgar Square in central London on February 13. A group has been set up to organize another one at Liverpool Street Station a week later.

The station has a large open space with a balcony surrounding it. User videos shot from the balcony and posted on Facebook showed every available inch of space filled with people, many of them cheering, though the event was billed as "silent."

Flashmobs -- groups of people meeting and all doing the same thing together in public, from dancing to freezing in place -- have become increasingly regular events around the world. iReport.com: See an organized mass pillowfight in Taiwan

London's Tate Modern art museum was the scene of a flashmob dance in 2007, and hundreds of people froze in place in Trafalgar Square, then formed a conga line in 2008.

Charlie Todd, a comedian and founder of the New York group Improv Everywhere, which organizes flashmobs, says the point of the group's "missions" is simple.

"We get satisfaction from coming up with an awesome idea and making it come to life," he writes on the group's Web site.

"In the process we bring excitement to otherwise unexciting locales and give strangers a story they can tell for the rest of their lives. We're out to prove that a prank doesn't have to involve humiliation or embarrassment; it can simply be about making someone laugh, smile, or stop to notice the world around them."