Screened at Berlin (Competition) Dir. Mike Nichols. US. 2000. 99mins.

Made in England by Mike Nichols and adapted from the Pulitzer Prize-winning play by Margaret Edson into a cable TV original for HBO in the US, Wit is in no sense a film that will travel far in the cinema. It is, however, an extraordinary effort by all concerned and, in particular, by Emma Thompson, who takes the leading part of an well-known but hardly well-loved academic who finds herself stricken with advanced ovarian cancer.

Thompson has seldom been better as this highly intelligent woman, a renowned expert on the metaphysical poetry of John Donne, who elects to face the severest chemotherapy course without much serious hope of recovery. As an actress, she has to progress from a doughty and disciplined academic who suffers fools, especially recalcitrant students, less than gladly to a virtually defenceless woman needing the final, almost childishly expressed comfort of the veteran teacher (Atkins) who started her on her route to success.

Thompson does not achieve this effortlessly but with extreme honesty, helped by the fact that the woman she plays has an ironic sense of humour and an acute awareness of what is happening to her. Nichols' camera seldom leaves her so that the film, which usually manages not to betray its origins as a play, becomes a tour de force for the actress. But this is not so much a star performance as a fearsomely felt one. It deserves the awards that will surely come its way.

The film, like the play, suggests that the literary scholar's fate is somehow bound up to her previous existence as a stern fighter for truth and knowledge. Now she has to fight a last long battle, as much against the medical profession as the disease. And it is one which can give her small victories along the way, against the specialist (Lloyd) who is very much her medical equivalent and the young clinical researcher (Woodward), his research-oriented assistant. To them she is simply another patient who may or may not further the cause of research. They seem to think that kindness is the equivalent of an emotional involvement that would make their jobs impossible.

She is aided in her fight against the dying light and the medics' extraordinarily comfortless attention by a private nurse (McDonald) whose performance in an admittedly easier role matches Thompson's.

Nobody lets this chamber piece down and its power is such that the hardiest cynic couldn't fail to be moved. Even the highly theatrical device of the leading character talking to the audience works on this occasion. The film may have its commercial limits - it's the opposite of a feelgood movie - but those who do see it may never quite forget the experience.

Prod co HBO Films, Avenue Pictures. Int'l sales: HBO Enterprises. Exec prods: Cary Brokaw, Mike Nichols. Prod: Simon Bosanquet. Scr: Emma Thompson, Nichols, based on the play by Margaret Edson. Cinematographer: Seamus McGarvey. Prod des: Stuart Wurtzel. Ed:John Bloom. Main cast: Emma Thompson, Christopher Lloyd, Eileen Atkins, Audra McDonald, Jonathan M Woodward