I think I should come clean and confess that I have not read Eric Lomax's highly regarded memoir about his time in a Japanese prisoner of war camp in the Second World War. Truth is, I'd never heard of it before settling down to watch Jonathan Teplitzky's film adaptation and didn't even know it was a true story. But should that matter? Regardless of its heritage, a movie should stand on its own merits.

Teplitzky's previous film, Burning Man, in 2011, had really caught my imagination and is well worth seeing. And with Oscar winner Colin Firth as the lead and Nicole Kidman as his lady, The Railway Man seemed intriguing.

But, although it feels somehow inappropriate to be critical of a movie that serves to remind us of the horrific experiences of captured British officers forced to build what was then known as the Burma-Siam railway, the film at times feels a bit remote and plodding.

Memories of that torturous time haunt Lomax, who has a bad case of post-traumatic stress that only his pals at the veterans club in Berwick-upon-Tweed can truly understand.

Then Lomax, who is a railway enthusiast meets Patti (Kidman) and falls in love instantly, though it is only after they marry that she finds out about his night terrors featuring the recurring appearance of Nagase (Tanroh Ishida), the Japanese Army officer who supervised his torture.

The lion's share of the story takes place in the jungles of Thailand, where stick-thin PoWs struggled to survive in gruelling conditions. Teplitzky has recreated this well.

The modern aspect is worthy but less compelling. I struggled to identify the period in which it was set - and how old Lomax was meant to be when fellow ex-PoW Finlay (Stellan Skarsgard) discovers that Nagase is alive and well and running a war museum that was once their prison camp.

Having sacrificed himself selflessly for the sake of his friends during imprisonment, Lomax must now decide if finding and punishing his torturer will help rid him of his demons.

Firth is a reliable presence in any film and does a good job convincing us of Lomax's mental suffering. Yet for all his noble acts, this is not a character you can warm to, even after discovering that his story is true.

Unlike the stirring Bridge On The River Kwai, there is just something missing from the whole experience.

I may have to read the book to find out what it is.