The language of disability has changed vastly since Peter Nichols' controversial yet celebrated A Day in the Death of Joe Egg had its world premiere at the Citizens Theatre in 1967. It is a curious thing that words like "spastic", freely and innocently used throughout the two hour long play, have a greater power to wound in the 21st century than they ever could in the decade it was written. And perhaps that is part of the value of this fascinating, witty and thought-provoking play.

Times have changed somewhat, although they probably have not changed as much as we would like to think. Here we have parents, driven to the brink of insanity and self-destruction, trying to cope with the personal difficulties and social prejudices associated with raising a child with cerebral palsy in 1960s England. A surprisingly modern play, it welcomes its characters to step outside of their existence, analysing their life story and frustrations with colour and vigour.

Miles Jupp and Sarah Tansey are excellent as Bri and Sheila, a couple struggling to reconcile their own emotions and marital problems. Jupp is superb as father Bri, storming around the stage with a manic eloquence and a receptive comic performance. Tansey, too, finds the vulnerability at the centre of her character, indulging her husband’s and introspectively pleading for answers with sincere passion.

Comedy is, as Nichols suggests, “a useful anaesthetic” to the severity of the play’s reality and director Phillip Breen has brought together some incredibly sharp wits. Olivia Darnley plays Pam, friend to the couple and smiling assassin, with all of the vicious inequality of the class system which she props up, and Joseph Chance plays husband Freddie with warmth and genuine compassion.

Despite only appearing in the last quarter of the play, Miriam Margolyes performance proves her worth as one of the finest female actors in British theatre as Bri’s mum Grace. Proving that you cannot spell "smother" without "mother", she elicits involuntary snorts of laughter from her audience, perfectly spinning Nichols' incidental, Bennett-like yarns on tea at the Odeon and the plight of the middle classes with masterful intonation and endless spirit.

When Nichols wrote A Day in the Death of Joe Egg, it was a revealing portrait of his own experiences: more than forty years later, Breen's production is an indictment, a shocking exposé of our treatment of the disabled in the past.