It's not hard to see why the French cinema director Alain Resnais was attracted to film Alan Ayckbourn's Private Fears in Public Places. Set in an unusual, celluloid structure of 54 short scenes, with no interval, the play focuses on six people trapped in separate but overlapping existences.

Private Fears - intended, according to the author, as a "film for stage" - dates from 2004, a year in which Ayckbourn wrote no fewer than four plays. After a run in Scarborough and a month in London, it went on to became the hottest ticket in New York, featuring among the year's top 10 theatre events.

Given this first-rate revival by Chris Honer and his excellent Library Theatre company it's easy to see why, despite its ultimately bleak vision of life for these mostly thirtysomething singletons, it achieved such success.

On Judith Croft's imaginatively compartmentalised set - a smart hotel bar, a nondescript office, a couple of dull sitting rooms and the stylish façade of an apartment block - scenes glide seamlessly and swiftly between these multiple fixed locations, adroitly lit by James Farncombe. Scarcely a scrap of furniture requires to be shifted, and there is no stage business to distract from the unfolding of these characters' lives - both public and private - or the subtly interlocking narrative.

Ayckbourn strikes a fine balance between farce and the work's dark-edged, even faintly disturbing undertones, and this fine cast tackles the tricky relationship between comedy and tragedy with a compelling confidence.

Olwen May as Charlotte, a woman with more than a few murky secrets, makes the transition from up- right office administrator, bursting with Christian values, to vamp with terrific panache. Caught up in the web she has disingenuously spun, Leigh Symonds plays her boss, an affable, boring estate agent. His mechanical bonhomie goes into overdrive when he becomes the recipient of what he imagines to be a coded message in the form of a porn video. His sister, whose low self-esteem has reduced her to seeking friendship through personal ads, is given a robotic brightness as well as a touching vulnerability by Alice James.

The self-centred, failed army officer Dan (Robert Perkins), despised by his military father, and the prissy, perfectionist Nicola (Imogen Slaughter) seem so immediately incompatible as a couple that it's a relief when they split up. Ambrose the barman, engagingly played by Malcolm James, is quite the nicest creation in this mildly gruesome array of people, a sad, sensitive man hounded by old demons including an appalling old dad.

Allowing us to see things from the perspective of more than one character as a life casually brushes against another, Ayckbourn intrigues us with his dramatisation of everyday events. You read between the lines to draw your own conclusions and it's a strength of the play, as well as the acting, that you certainly find yourself wondering, not very optimistically, about these people's futures. Yet the humane sympathy the writer appears to have for his characters is never at the expense of a great line or situation. There are some tremendously funny moments in Private Fears despite the alternately bitter twists and mysterious turns as these fragments of human lives are turned over and inside out.

Now, happily, recovering from the stroke he suffered in February, Ayckbourn will return shortly to the Stephen Joseph Theatre in Scarborough to direct his latest play, If I Were You. Whether or not it contains the same kind of grey shades and ultimately bleak material as Private Fears remains, tantalisingly, to be seen.