Pictured: The terrifying moment armed police held down an innocent man on train and put a gun to his head

Officers then dragged him to his feet and frogmarched him away to be searched and interrogated.

Minutes later, however, he was released without charge after it became clear that they had seized entirely the wrong man.

On emerging from the train, this innocent passenger was greeted by two police officers with pistols and ordered to lie on the platform

It later emerged it was a case of mistaken identity and the man was released without charge

Fortunately no shots were fired in the incident at Bournemouth station. But it bore disturbing echoes of the Jean Charles De Menezes incident, when police hunting the 21/7 bomb plotters shot an innocent man dead at Stockwell tube station in South London three years ago.

The Bournemouth incident, captured on a passenger's mobile phone camera, came after armed officers were called to the station to arrest a suspect following a previous 'armed incident'.

A colleague travelling on the train wrongly identified the 21-year-old passenger as the wanted man in that case and tipped off colleagues.

A witness said: 'There was a large group of us queueing for tickets when armed police pulled up outside the station. There were about ten officers, some of them armed with handguns, and a police dog.

'I heard one say, "Don't let anyone off the train or leave the platform". The exits were all blocked off and then the 6.05pm train pulled up.'

The witness added: 'As soon as the doors opened and the man stepped on to the platform, he was ordered to lie down. His arms were stretched out and his legs crossed.

'Two police officers drew their weapons. After searching his bag they took him into a disabled toilet cubicle, possibly to search him, before several officers escorted him away. It was a terrifying incident.'

Dorset police yesterday confirmed that the man, whose identity has not been released, was detained by mistake and he was now being offered 'appropriate support'.

A spokesman said the man had been released without charge on Saturday evening. 'Dorset police were advised by Hampshire constabulary of an earlier armed incident in Basingstoke.

'A man was identified by a police officer on a train travelling into Dorset. The train stopped at Bournemouth and the man identified was detained by two Dorset police firearms officers just after 6pm.

'Inquiries into the circumstances of the arrest are continuing. No shots were fired and no one was injured.'