Inspired acting makes this a chilling play. The performances are eerily right. Tim Dutton as O’Brien, the false friend, is as smooth as a blender. If anyone is going to convince you that two and two could make five, or six... or sometimes three... he will.

By the end of his torture and interrogation of the earnest Winston Smith, I was starting to doubt everything I know - except that I know a good performance when I see it.

Mercifully, George Orwell writing his book 1984 in 1949 - almost as long ago now as it was then in the future - didn't get everything right.

It turns out that in the West, it is more effective to dull our minds by padding us in comfort and complacency than by deprivation. In Communist Russia, there may have been queues for food but here for the past three decades we have been too dizzy choosing between 20 types of spray-on happiness and instant friendship to worry too much about politics.

The effect is the same. We bought Doublethink. While we are getting poorer, we are told we are getting richer. While our health service deteriorated we believed it led the world. We kept our proud illusions about "British Justice" despite so many celebrated travesties and evidence of a police force which was racist, lying and corrupt. Today, we keep hearing that unemployment is going down but there don't seem to be any more jobs.

And finally, we have broken from our political apathy only for elections like Orwell's "Hate Week" blaming all our troubles on "the immigrants." Blaming the state of the nation for the latest people to join it. My goodness, they must have been busy.

Meanwhile, we have indeed been subsumed by America and used for its wars, as Orwell foretold. In 1984, set in London, Britain has been renamed "Airstrip One".

Both the book and the play are concerned with the global and the individual. Orwell predicted that there would always be a war somewhere, saying that the idea was not to win. Conflicts would no longer be over land or minerals, nationhood or ideology. War would be an end in itself.

As Orwell says, war uses up resources and keeps people in a hierarchy. If the lower orders have the same earthly comforts as their betters, they can equal their betters. This happened for a brief period in the 1960s and 1970s when high standards of health, housing and education removed the barriers to social mobility and we spoke of meritocracy. I haven't heard the word for 30 years.

These are huge themes to put on a stage, even if they are told in the book through the simple love story of Winston and Julia whose affair breaks Party rules.

This version, written and directed by Robert Icke and Duncan Macmillan keeps faithfully to Orwell's work. The cast's well-observed performances have just the right blend of mechanical thought and human frailty to draw the audience into the world they create. The staging and set cleverly reflect Orwell's prescient ideas shaped by the time he lived in. It is futuristic and 1940s at the same time.

Matthew Spencer is an endearing, all too human, Winston, brave and frightened at the same time, as surely we all are, Ben Porter as Syme and George Potts as Parsons (in Orwell's words: "an active man of paralysing stupidity") are wittily real as Winston's work colleagues. Just the sort of people you meet in a work canteen: Syme enthuses about the hidden detail of his job. It would bore anyone else but his eyes light up.

Parsons is bursting with pride about his precocious little girl, a member of the "Spies" (Orwell's Stalinist version of the Scouts) a spiteful little thing denouncing adults to the Party, which her father boasts is "not bad for a seven-year-old".

Mandi Symonds brings warmth to her several female roles. It is Janine Harouni as Julia, a character an intriguing blend of passion and coolness who is truly the rebel without a cause. She is defiant not because of any principled stand but because she likes sex and wants to have it.

Winston tells her: "You're only a rebel from the waist downwards", which she is delighted with. But Orwell says: "In the ramifications of Party doctrine she had not the faintest interest. One knew that it was all rubbish so why let oneself be worried by it?

"In a way, the Party imposed itself most successfully on people incapable of understanding it. They could be made to accept the most flagrant violations of reality because they never fully grasped the enormity of what was demanded of them and were not sufficiently interested in public events to notice what was happening."

Or as Jesus Christ is said to have put it more succinctly: "Forgive them Lord for they know not what they do."

Great play, much to Doublethink about.