Richard Eyre makes an absorbing and gripping film from Zoë Heller's Booker-shortlisted novel which builds tension around the fascination of Judi Dench's veteran history teacher with new art mistress Cate Blanchett in a north London school.

From the start, Dench's voiceover uncovers her real personality: she's bitter, lonely and vindictive, and especially self-deluding, seeing herself at one time as "nurse, beloved friend and wise counsel" when "vengeful leech" might be more appropriate. She discovers Blanchett having sex with an underage student, knowledge which gives her an opportunity to get close to the unhappy wife of Bill Nighy's age-gapped husband. The acting is a masterclass and screenwriter Patrick Marber and cinematographer Chris Menges make this a fine team of British talent.

On the face of it, there are no likeable characters on show - even the 15-year-old object of Blanchett's affections is revealed to be a liar - but as Eyre says in his director's commentary, "You have pity and sympathy for two women who have done bad things." Where Marber's script for Closer never made you warm to its glacial, self-absorbed characters, these flawed people are memorable and, to a degree, even understandable thanks to the subtlety of the performances, both central and minor.

Eyre uses a working comprehensive school to root the film in reality and there are no dull patches in an enveloping tragedy with welcome hints of black comedy. After the Dame's title role in Iris, it's notable that Dench has given easily her best two screen roles in Eyre's films.