It began as an argument about a train fare and has evolved into a nationwide debate about the merits of making a public intervention.
When Falkirk student Sam Main was filmed being forcibly ejected from a train by another passenger after refusing to pay for a ticket it triggered a chain of events that no one involved could have predicted.
The incident last Friday night was recorded by another traveller on a mobile phone and uploaded to the website YouTube, where it has been viewed more than one million times in the space of four days.
Debate has since raged about whether Alan Pollock, an investment banker from Stirling, was right to physically remove Mr Main from his seat and throw him onto the platform at Linlithgow station after the 19-year-old refused to pay for a ticket.
The Heriot-Watt University student claimed in a radio interview yesterday that the argument with the conductor was the fault of another Scotrail employee, who had advised him to buy two single tickets for his return journey from Polmont to Edinburgh Park.
He said that when he tried to explain the situation to the conductor he was told to buy another ticket or leave the train.
But The Falkirk Herald can reveal that this explanation has been dismissed by a rail industry insider.
The source said: “The claim he was advised to buy two single tickets does not ring true.
“Clearly, it is cheaper to buy a standard day return. And at all times on the tape, he shows only one ticket. It was for his outward journey in the morning from Polmont to Edinburgh Park - not for his return trip at night.”
In the video, Mr Main - a former pupil at St Mungo’s High School - can be seen arguing with the condcutor, who tells him to depart the train or buy a ticket.
Mr Pollock then stands up and appears to ask the conductor if he would like Mr Main to be removed.
He then grabs the student from behind and forcibly ejects him from the carriage.
When Mr Main tries to get back on, saying that he has left his bag on the train, Mr Pollock again pushes him back off.
It emerged yesterday that a complaint had been made to British Transport Police against Mr Pollock.
A spokesman for the British Transport Police said: “We are aware of the YouTube video and can confirm we are investigating the circumstances surrounding the incident and our enquiries are ongoing.
“British Transport Police appreciates the assistance of members of the public who report crimes or anti-social behaviour of any kind.
“If you are unfortunate to be the subject of, or a witness to, criminality on trains or anywhere on the rail network, you should immediately contact BTP in the first instance on 0800 40 50 40 or in an emergency dial 999.”
A spokesman for Scotrail said: “The conductor, who is on annual leave, is co-operating fully with ongoing inquiries by the company and British Transport Police.”
To view the video, click here YouTube video footage