REVIEWED - NOTES ON A SCANDAL:  IT'S hard to imagine a brainstorming meeting in a Hollywood boardroom where anyone might ever…

REVIEWED - NOTES ON A SCANDAL: IT'S hard to imagine a brainstorming meeting in a Hollywood boardroom where anyone might ever suggest casting the venerable Dame Judi Dench in the role of a stalker. Full credit, then, to Richard Eyre who directed Dench as Iris Murdoch in Iris - for having the imagination to cast her so firmly against type in Notes on a Scandal.

And even more credit to Dench for taking on the role, and for having very bad hair throughout the movie.

The protagonists are aptly named. Dench plays Barbara Covett, a North London teacher who is as stern and imperious in the classroom as Dench is as M in the Bond movies. Cate Blanchett co-stars as her new colleague, art teacher Sheba Hart, who shares her full name (Bathsheba) with a Biblical adulterer.

Outside of school, Barbara is lonely and insecure, pouring her delusions and caustic observations into her diary, which doubles as narration in the film, and with all the time in the world to become more obsessive about this attractive new teacher. Sheba lives in what Barbara describes as "bourgeois Bohemia" with her husband Richard (Bill Nighy) - who is closer in age to Barbara - and their two children, one of whom has Down's syndrome.

While we ponder whether Barbara's deep interest in Sheba is platonic or sexual, Sheba is unexpectedly drawn to one of her 15-year-old pupils, confidently played by Irish actor Andrew Simpson as a precocious combination of wide-eyed innocence and raging hormones. Refreshingly, Patrick Marber's screenplay doesn't bother to remark on the fact that Simpson's Steven Connolly and his parents have Northern Ireland accents; they just happen to live in London.

The film is based on Zoe Heller's novel, What Was She Thinking? Notes on a Scandal, which Marber has reshaped as a taut psychodrama condensed into a flab-free 92 minutes that never flags. The outline suggests a same-sex spin on Clint Eastwood's Play Misty for Me and Adrian Lyne's tawdry Fatal Attraction, but Marber digs deeper than either film.

Eyre's sole misstep is the movie's strident Philip Glass score, relentlessly swirling to reflect Barbara's inner turbulence and Sheba's escalating anxiety. Such arch underlining is superfluous, given that the performances from Dench and Blanchett are so perfectly judged in their own right.

Both have demonstrated remarkable versatility in their prolific screen output since they played Elizabeth I at different ages in the 1998 releases, Shakespeare in Love and Elizabeth. Together in Notes on a Scandal, they are a potent combination as the pressure builds on both their characters and Sheba's vibrancy gives way to vulnerability while Barbara becomes more pathetic than sympathetic.