Translating Zoe Heller’s novel “Notes on a Scandal” onto the bigscreen was “phenomenally difficult,” says theater vet Eyre.

The book is narrated by a character, played onscreen by Judi Dench, who depicts herself as a sympathetic observer of the downfall of a fellow teacher (Cate Blanchett). But her unconscious malevolence is ultimately revealed as the principal cause of her friend’s undoing.

The unreliable narrator is a classic literary trick that doesn’t work easily in cinema.

“You can’t reveal information subjectively in that way on film,” explains Eyre, who last worked with Dench on “Iris.” “The moment you put a character onscreen, you objectify that character.”

So the director must find a way of evoking a complex response by the audience to a character who might easily seem simply monstrous.

“People do seem to have found that not only are they appalled by this character, but they are also somehow drawn into her spider’s web.”