Stars: Jim Sturgess, Ed Harris, Colin Farrell, Saoirse Ronan, Mark Strong.

(opens Boxing Day) 132 minutes.

★★★★

AS suggested by the title of the memoir on which the film is based, The Long Walk: The True Story of A Trek To Freedom, The Way Back is no stroll in the park. Director Peter Weir 2who gave us Gallipoli, Witness, Master And Commander and The Truman Show to name but a few – ives the story an epic feel as prisoners from a Russian gulag make their bid for freedom.

Breaking out of their Siberian prison during World War Two is the easy part as the only route to freedom takes them across the frozen wastelands of Siberia and the blistering heat of the Mongolian desert.

This means that the movie looks stunningly beautiful, although the hardship is endless. Too hot, too cold, not enough food, no water are the main problems they face on the trek.

The story, incidentally, was inspired by a book by a man who claimed (some say he’s fibbing) to have made the walk. Weir has combined it with testimony from people who have trod the 4,000 mile route so it all feels pretty authentic. Jim Sturgess is the Polish officer sent to a Russian gulag in Siberia accused of being a spy. He meets a prisoner (Mark Strong) who outlines an escape plan but, when push comes to shove, he refuses to leave the camp.

Others in the escape party are braver. Like highly tattooed Russian criminal Valka (Colin Farrell) and the US prisoner enigmatically calling himself Mr Smith. A teenage refugee (Saoirse Ronan, from Atonement and The Lovely Bones) joins them en route.

It’s a long journey for us as well as them, but Weir ensures that we’re willing them to overcome their hardship and get away, although we know from the opening caption that they won’t all make it.