The first half of this New Zealand adaptation of a novel by Lloyd Jones presents the appearance of a sentimental feelgood movie – a kind of Dead Poets Society or Goodbye Mr Chips set on the tropical Pacific island of Bougainville in 1991.

Despite a guerilla war going on in the background, white Englishman Mr Watts (Hugh Laurie), takes great pride in playing the role of the inspirational teacher and turning on his local pupils to the joys of Charles Dickens’s Great Expectations in classic cultural imperialist style.

Then something unexpected happens and what had looked to be a film you could safely take your granny to see turns into something liable to cause severe family recriminations and knife fights. Director Andrew Adamson, the director of films in the Shrek and Narnia series, certainly makes the early scenes easy to slip into without overloading the sentiment. Xzannjah (just the one name) is charming as his teenaged star pupil, Matilda, imagining herself and other locals in a localised revision of the Dickens tale that runs in a parallel story. What he hasn’t been able to do is pull offthe story’s central narrative shock in a way that preserves its unity rather than splitting it right down the middle.