Panicked passengers smashed their way out of a tube train at Clapham Common with the doors failing to open as the carriage filled with smoke.

The London Underground train leaving Clapham Common station at around 5.45pm on May 5 last year was unexpectedly stopped by a passenger emergency alarm due to smoke and a burning smell.

This caused panic among approximately 500 passengers and the six-carriage train halted with two cars inside the tunnel and the remaining carriages on the platform.

Frustrated by the train doors not opening, around 100 passengers evacuated themselves through the doors and windows.

Some passengers broke them, partially damaging the train and causing minor injuries.

Four and a half minutes after the sudden halt, the staff at the station manually opened the doors.

Although the injuries were minor, the severity could have been worse due to the narrow platform of the Clapham Common station.

There was a potential risk of passengers falling onto the tracks and coming into contact with the conductor rails or the oncoming trains on the southbound line.

The investigation by the Rail Accident Investigation Branch (RAIB), revealed that passengers' fear and subsequent behaviour resulted from their perception of substantial fire risk and lack of timely and communication or action from the London Underground staff.

It also highlighted the staff's unpreparedness in effectively identifying and managing incidents where passengers' behaviour can quickly escalate.

The report noted that this incident is similar to a previous train disturbance at Holland Park station, where passengers forcefully escaped in 2013 after the doors were not opened in case passengers climbed onto the live tracks as the train was not fully in the station.

It underlines a potential issue; that London Underground failed to retain and apply learnings from that incident.

It also suggests an oversight of the risk involved when passengers self-evacuate from trains, especially those stationed at tight island platforms.

RAIB has forwarded three recommendations to London Underground.

Firstly, to develop procedures and training to guide the staff when confronted with unusual events.

Secondly, not to downplay previous incidents and ensure recommendations are effectively implemented.

Lastly, to review risk assessment processes to identify and assess risks associated with unusual train events and specific locations.

Andrew Hall, chief inspector of Rail Accidents said: “Out-of-course events can rapidly escalate into emergencies if not responded to promptly and effectively.

“During this incident staff didn’t fully appreciate the emerging safety risk when passengers’ behaviour began to escalate as they became increasingly anxious.

“When passengers did not receive suitable information about the nature of the incident and the actions they should take, nor see action they would have expected to be taken, they turned to desperate measures to self-evacuate.

“RAIB investigated a similar incident at Holland Park in 2013 and for a number of years that incident was used as an example to train staff about how to respond to such out-of-course events.

“However, it was subsequently removed from the training syllabus and since then knowledge of the lessons learnt may well have begun to fade.

“This incident again demonstrates that learning from past operational incidents needs to be retained by organisations.”