Seventy-five years after George Orwell wrote his dystopian masterpiece about a world in which a totalitarian state has criminalised freedom of thought, its questions about resistance and humanity seem no less powerful and pertinent. But there is high risk in adapting a story whose imagery and ideas have become so much a part of the cultural lexicon – from Room 101 to Big Brother’s all-surveilling eye.

This economically delivered production by Lindsay Posner keeps you gripped, although Ryan Craig’s adaptation flattens the book’s depth and speaks rather too prosaically, even daring to change the plot to circumvent some of the complexities of its staging.

Mark Quartley as Winston, the jaded apparatchik at the Ministry of Truth whose rebellious spirit is ignited by an illicit affair, emanates mostly bewilderment here. Eleanor Wyld, as his lover, Julia, has a similar look to Suzanna Hamilton in Michael Radford’s iconic film and is a spirited presence but the relationship between these central characters does not come to life. There is a significant lack of fizz between them which undercuts the love story and subsequent betrayals.

Winston’s sadistic superior, O’Brien (Keith Allen), played by Richard Burton in the film, has a more active role in Winston’s entrapment here. Allen is a creepy figure with glasses and goatee, sitting on the sides of the exposed stage, in watch, when he is not performing. It is a capable performance which emanates controlled rage. David Birrell as Winston’s neighbour, Parsons, is effective too, reminding us that even when citizens abide by the rules, they are not immune from punishment.

Big Brother’s eye dominates the stage with several parts played only on screen, including Finbar Lynch as Goldstein, the head of resistance forces against Oceania. The eye is over-familiar and feels a little like a totalitarian version of Alexa, but Justin Nardella’s set and video design is incredibly arresting and original in spite of it, working with Paul Pyant’s dramatic lighting. Winston’s terror of the rats in Room 101 is enacted in darkness and is infused with hideous threat.

Ultimately, the production does convey the chilling sense of a State attempting to control reality, and quash the human spirit that rises up against it, even if too many of Orwell’s ideas feel attenuated and over-simplified.

• At Theatre Royal Bath until 28 September. Then touring.