Woman In Mind: One woman's struggle to distinguish between humdrum reality and the perfect imagined life, at Chichester Festival Theatre

Susan is the female equivalent of a Walter Mitty – that fictional character who fantasises about a life much more exciting than his own. Except in Susan’s case it is not excitement that she craves – but a perfect family life that in her real world seems impossible to attain.

Her son has run off to a silent religious order and says nothing. Her dull husband forever writing his book about the history of the parish says far too much. Her sister-in-law, whose conversation is limited to the appalling food and beverages she produces with unfailing regularity, shows no signs of moving out the bourgeois family home.

So she inhabits an imaginary world in a gorgeous mansion, with a daughter on the brink of marriage and an adoring husband. Her flamboyant brother servers only the best vintage champagne. They all dote on her.

Then she steps on the garden rake and takes a bashing to her head. As she regains consciousness in the garden the real and the imagined blend.

In some respects Woman In Mind follows the Ayckbourn formula – light, reassuringly familiar, and funny at the start, before becoming progressively darker until a brutal climax in the final act. But in other ways, this is quite different in tone from the normal romp penned by this master of his trade.

From the outset, this is very much a personal account of one woman Susan, played with mesmerising brilliance by Jenna Russell. There is also a sense too that Ayckbourn has a profound message to lay down – influenced, many have suggested, by people and events in his own life.

So the mental torment of the lead inevitably has a stinging effect on all who witness is, not least those whose lives have been directly touched by mental illness.

Nor does the author give too much away. So from the outset there are no clear dividing lines between that which is the real and the imagined life. Perhaps, after all, Susan really does inhabit a blissful family world and the bland, dull alternative is not her reality but her nightmare.

Whatever the interpretation, there can be little dispute that this is superlative drama. My goodness, how we are going to miss our artistic director Daniel Evans when he leaves us next year for even greater triumphs yet to come.