Passengers were forced to "break out" of Sutton rail station after staff closed it for the night before the last train had arrived.
Scores of people heaved up metal shutters and crawled to freedom after finding themselves locked in the station in the early hours of Sunday morning.
An estimated 100 passengers were on board the train from London Victoria when it terminated in Sutton at about 1.30am on Sunday.
Footage sent to the Sutton Guardian showed four men holding up the shutters to the station's main entrance in High Street as a stream of people crawl out.
Harry Nelson, who shot the clip on way his way home to Banstead, said: "I was on the last train back to Sutton and got off the train along with perhaps 100 other people. The ticket barriers were open but the shutters were shut.
"People starting heading to the second exit, which we thought may have been open, but we noticed people were turning away from that as well.
"There was kind of an air of panic as we realised we were trapped in the station.
"A few of us took the initiative to force open the shutters and break out. It took about five or six of us to get our hands underneath and just force it upwards.
"We managed to raise it upwards by about a metre and people managed to just crawl out as people held it open for them."
The 25-year-old, who had been drinking in Balham after watching the English rugby team clinch the Six Nations grand slam, said: "There were absolutely no staff. We were looking around for staff but there was no one at all.
"I had an idea that they had probably clocked off without realising not all the trains had got back. This was the last one but I don't think it was running late at all."
But Southern, which manages Sutton station, said a member of staff had been at the station checking that all passengers had got off the train.
A spokesman added the train was not usually scheduled to call at the station, meaning staff had not expected it and closed the shutters before it arrived.
He said: "Unbeknownst to passengers, a member of staff was on duty at the station at the time, ensuring that the train they came in on was empty of passengers in order to return to the depot.
"The shutters had been closed at the end of the normal day's service, but the later train was an unexpected arrival so the staff member went to attend to the train as soon as it arrived.
"It is not a case of there being nobody about and the staff had gone home and left people shut in there."
The shutters were undamaged and were locked again by staff after passengers had left, he added.