Forgiveness: the 9th (out of 12) Step in Alcoholics Anonymous’ recovery program – making amends for the harm caused to others during one’s addition. And so Alcie-on-the-mend Keith sits awaiting the arrival of his ex-foster parents, nervously jiggling his leg and feigning engrossment in a book.

Rob Hayes play, directed by Tom Attenborough for Trafalgar Studios, delves into very unexplored territory – the destruction brought about from addiction and its far-reaching repercussions. Violent, shocking and very, very sad it is, but not without its moments of hilarity which a bearded Blake Harrison delivers with superb ease and timing.

The bleak box that Keith calls home – almost too paltry to be called a hovel – gives a Samuel Beckett feel of claustrophobia and mirrors perfectly the absence of hope both the family and the audience feel by the end. Francesca Reidy’s design also leaves room for some comedy as Keith talks through a hole in the wall from the kitchen into the bedroom/living area.

Wendy Nottingham and Barry McCarthy are incredibly believable as the long-suffering couple that have been dragged through Keith’s rollercoaster ride of booze-fuelled delinquency. By the end of the 95 minute play one feels as much a part of the trauma as if one had grown up in the household. Ben Dilloway plays a small but important role as the son of the teacher now left a vegetable thanks to Keith’s violence and gives the part all the menace and foreboding it requires.

Harrison must also be commended for the unfaltering vigour he gives the lead role without resorting to self-indulgence – confirming he is just as successful on stage as he is on screen.

While Step 9 (of 12) has drawn to a close, Greenhouse Production’s Mercury Fur – which enjoyed spectacular reviews during its run at the Old Red Lion – is transferring to the Studios from Tuesday 29th May, starring Step 9 (of 12)’s Ben Dilloway as bad-man Spinx. Buy your tickets now before they are all gone.