WHEN we first meet ardent train enthusiast Eric (Colin Firth), he is safely ensconced in a first-class carriage, casting nervous glances at the lady sitting opposite.

Eventually he strikes up a conversation with Patricia Wallace (Nicole Kidman) and learns she is visiting the north of England based on recommendations from a friend.

"With all due respect to your friend, if all he's mentioned is vodka, he's only scratched the surface of Warrington," sweetly blusters Eric.

He engineers another meeting with Patti further up the line and they fall in love and marry.

It quickly becomes clear to Patti that there is something in Eric's past which is troubling him, but her efforts to help are swatted aside.

"You will never again attempt to discuss matters which do not concern you. There's no objection, I hope?" Eric firmly tells his wife.

So she seeks out best friend Finlay (Stellan Skarsgard), hoping he can reveal the scars of the past and ease her spouse's suffering.

"A lot of men went through something you can't even begin to imagine," Finlay tells her.

Ultimately, he recounts to Patti, and us, the horrors faced by young Eric (Jeremy Irvine) and fellow soldiers at the Sakamoto Butai camp.