Without doubt, the performances are excellent. Skipping between the lovers' meeting as young academics at Oxford and their twilight years, the film splits acting duties between Kate Winslet and Hugh Bonneville, and the more mature Judi Dench and Jim Broadbent. Both pairings are amply provided with emotional trauma, and rise to it magnificently. As the older Bayley battles to keep his wife's fading mind alive as even the most basic daily tasks defeat her, his younger self battles jealousy and his own sense of inferiority as Iris flits, firefly-like, through a world of intellectual glamour and casual sex that he feels excluded from.
It's a fascinating odd-couple relationship, but in the end, Bayley's viewpoint is not quite enough for us. Despite their genuine closeness, Iris has always been an enigma to him - and thus, she remains one to us. The inexplicable nature of genius may be a fact of life, but film demands empathy, and we struggle in vain to find anything in her to identify with. Without that vital - perhaps impossible - insight into her contradictory character, her sexual experimentation and intellectual superiority threaten to turn her into some kind of surreal chauvinist cliché; the tart with a brain, perhaps?
This is a film worth seeing for the quality of the performances alone, and the tragedy of her deterioration carries you through a first viewing satisfactorily. But in retrospect, the experience is dry and a little alienating, leaving us very much on the outside, peering in at the bright and the beautiful.