A student taking a photograph of a train for a school project was arrested because she could have been part of a "terrorist plot", it is claimed.
Chris Ward said he was at Tattenham Corner station last week when he heard about the alleged arrest.
He said: "This very brief story shows just how stupid we have become in this country.
"I was queuing at Tattenham Corner railway station this morning for a ticket.
"A very nice lady was complaining to the ticket man. Her A Level student daughter, at a local school, was arrested for taking a photo of a train leaving Tattenham Corner station.
"The daughter had explained that she was doing a piece of work for school on local travel facilities.
"The girl’s camera was confiscated and the pictures of the train deleted. Apparently this was all done because ‘she could have been part of a terrorist cell plotting some form of attack on the train’.
"I find this just incredible."
A Spokesperson for the British Transport Police was unable to comment on the incident without the date on which it occurred, but confirmed it would not be illegal to take photographs for a school project under general law.
He said: "You are allowed to take photographs on stations if it is for personal use.
"For any commercial photography, you must seek permission from the appropriate train operator or from Network Rail at the 17 major stations.
"You are not allowed to use flash photography on platforms as it may distract the attention of train drivers and train dispatch staff and is therefore a potential safety hazard.
"You are also not allowed to take photographs of security related equipment, such as CCTV cameras."
But police can use their powers under the Terrorism Act to stop-and-search individuals if they believe they may be a terrorist threat.
In 2009, then Conservative MP for Central Croydon, Andrew Pelling, was stopped by police for taking photographs of East Croydon station.
He produced his MP’s ID and told officers he was taking the photograph for use in parliament, but his bag was still searched.
Have you been stopped taking photographs at a railway station or know anyone who has? Email firstname.lastname@example.org