The Royal&Derngate season celebrating the playwright's 70th birthday opens with a work from 1976, Just Between Ourselves, commonly acknowledged as a 'breakthrough' work. The two subsequent plays (one of which will be directed by Ayckbourn himself) date from 1988 and 2004, to give an overarching view of the writer's work throughout his career.

Just Between Ourselves sees Ayckbourn first moving into the tragic comedy arena which has become his trademark style. It is very, very, funny, with the set piece which closes the first half up there with anything any of the classic Whitehall farces offers.

But it is also utterly heartbreaking. The final moment of a depressed wife desperately trying to blow out a candle on a birthday cake is as tragic as anything from Lear or Macbeth. It was the latter's 'out, out brief candle' which hovered in my mind as poor Vera pursed her lips - and I wondered if husband Dennis would be finding this as funny as he had everything else about his wife's descent into the pit.

Dorothy Atkinson (pictured) gives a superb performance as Vera, delicately balancing on the tightrope between laughter and tragedy and making a moving but barely articulate appeal to husband Dennis for 'help - just help.' She knows what she wants, but he doesn't, apart from the mending of kitchen appliances.

He, if we're charitable, is probably seeking refuge in finding everything 'a bit of a laugh'. Kim Wall (pictured) is simply wonderful as the insensitive husband. If he can't listen to his wife's problems, he certainly isn't going to be any help to his new friend Neil, who has marital issues of his own - not least his wife's sex drive.

Both Kim Wall and Matthew Cottle, as Neil, display extraordinary skill and spot-on timing in one of the play's funniest incidents as the latter opens his heart only to be drowned out by the insensitive clatter of a sander. A fantastic moment combining the lightness and darkness of Ayckbourn marvellously.

Kim Wall also brings the house down with an outrageously obvious piece of body language as he sidles away from Neil's angry (and by this time drunk) wife Pam when she starts to talk about sex.

Pam ('the youngest supervisor they ever had') is another brilliant turn, with Lucy Briers leaving us in no doubt that her sharpness and aggression clearly hides bitter disappointment.

The only member of the family who seems to emerge triumphant is Marjorie, the mother of Dennis, deftly played by Marlene Sidaway. She has a telling scene in the garden wrapped in a blanket which foreshadows V's final breakdown. But where the wife is left with barely the will to live, Marjorie emerges triumphant with that one-candle cake.

The true tragedy seems to be that neither she nor her son really know what's going on. If she does, she's one of the worst monsters ever to be seen on a stage.

Absolutely terrific cast and pitch-perfect performances, wonderful set and lighting, and a sure touch by director Mark Rosenblatt, who lets us see the real tragedy behind seemingly ordinary lives and relationships. Yet another triumph, a rib-tickling, eye-watering one, for R&D, and, once again, everything totally generated in-house as part of the 'Made in Northampton' campaign by one of the country's most exciting venues.

To find out more about the productions and events taking place throughout the summer as part of Royal & Derngate's Ayckbourn at 70 festival, visit www.royalandderngate.co.uk or call 01604 624811.