Why should we still read George Orwell on politics? Until 1989, the answer was plain. He was the writer who captured the essence of totalitarianism. All over communist-ruled Europe, people would show me their dog-eared, samizdat copies of Animal Farm or Nineteen Eighty-Four and ask: “How did he know?”

Yet the world of Nineteen Eighty-Four ended in 1989. Orwellian regimes persisted in a few remote countries, such as North Korea, and communism survived in an attenuated form in China. But the three dragons against which Orwell fought his good fight — European and especially British imperialism; fascism, whether Italian, German or Spanish; and communism, not to be confused with the democratic socialism in which Orwell himself believed — were all either dead or mortally weakened. Forty years after his own painful and early death, Orwell had won.

What need, then, of Orwell? One answer is that we should read him because of his historical impact. For Orwell was the most influential political writer of the 20th century. This is a bold claim, but who else would compete? Among novelists, perhaps Alexander Solzhenitsyn or Albert Camus; among playwrights, Bertolt Brecht. Or would it be a philosopher, such as Karl Popper, Friedrich von Hayek or Hannah Arendt? Or the novelist, playwright and philosopher Jean-Paul Sartre, whom Orwell privately called “a bag of wind”? Take them one by one, and you will find that each made an impact more limited in duration or geographical scope than did this short-lived, old-fashioned English man of letters.

Worldwide familiarity with the word “Orwellian” is proof of that influence. “Orwellian” is used as a pejorative adjective, to evoke totalitarian terror, the falsification of history by state-organised lying and, more loosely, any unpleasant example of repression or manipulation. It is used as a noun, to describe an admirer and conscious follower of his work. Occasionally, it is deployed as a complimentary adjective, to mean something like “displaying outspoken intellectual honesty, like Orwell”. Very few other writers have garnered this double tribute of becoming both adjective and noun.

Everywhere that people lived under totalitarian dictatorships, they felt he was one of them. The Russian poet Natalya Gorbanyevskaya once told me that Orwell was an east European. In fact, he was a very English writer who never went anywhere near eastern Europe. His knowledge of the communist world was largely derived from reading.

Three personal experiences had transformed his understanding. First, as a British imperial policeman for five years in Burma he was himself the servant of an oppressive, though not a totalitarian regime. By the time he resigned, he had acquired a lifelong hatred of imperialism and also a deep insight into the psychology of the oppressor. Then he went to live among the “down-and-outs” in England and in Paris. So he knew at first hand the humiliating unfreedom that comes from poverty.

Finally, there was the Spanish civil war. Spain, for Orwell, meant the experience of fighting fascism and getting a bullet through his throat. But still more important was the revelation of Russian-led communist terror and duplicity, as he and his comrades in the heterodox Marxist POUM militia were hunted through the streets of Barcelona by the communists who were supposed to be their allies. Of the Russian agent in Barcelona charged with defaming the POUM as Trotskyist Francoist traitors, he writes, in Homage to Catalonia, “It was the first time that I had seen a person whose profession was telling lies — unless one counts journalists.” The tail sting is typical black humour. It also reflects his disgust at the way the whole leftwing press in Britain was falsifying events that he had seen with his own eyes.

As he says in his 1946 essay Why I Write, after Spain he knew where he stood. He had earlier adopted the pen name George Orwell in preference to his own, Eric Blair, but it was after Spain that he really became Orwell. Every line of his writing was now to have a political purpose. Imperialism and fascism would remain major targets of his generous anger. But the first enemy would be the blindness or intellectual dishonesty of those in the west who supported or condoned Stalinist communism — ever more so after the Soviet Union became the west’s ally in the war against Hitler. And so he sat down to write a Swiftian satire on Stalinist Russia, with the communists as the pigs in a farm run by the animals. “Willingness to criticise Russia and Stalin,” he wrote in August 1944, “is the test of intellectual honesty.”

The rejection of Animal Farm by several British publishers, because they did not want to criticise Britain’s heroic wartime ally, showed what he was up against. When it was finally published in Britain in 1945 (and the US in 1946), the book was a political event, helping to open the eyes of the English-speaking west to the true nature of the Soviet regime. One might call this the Orwell effect. Nineteen Eighty-Four, with its more generalised dystopia, became another defining cold war text. Not accidentally, the first use of the phrase “cold war” recorded in the Oxford English Dictionary comes from an article by Orwell.

In short, he was more memorably and influentially right than anyone, and sooner, about the single greatest political menace of the second half of the 20th century, as well as seeing off the two largest horrors of the first half. But those monsters are dead, or on their last legs. To say “read him because he mattered a lot in the past” will hardly attract new readers to Orwell.

Fortunately, there is a more compelling reason why we should read Orwell in the 21st century. This is that he remains an exemplar of political writing. Both meanings of “exemplar” are required. He is a model of how to do it well, but he is also an example — a deliberate, self-conscious and self-critical instance — of how difficult it is.

In Why I Write, he says that his purpose, after Spain, was to “make political writing into an art”. Animal Farm is the work in which he most completely succeeded. In his “little fairy story”, artistic form and political content are perfectly matched — partly because they are so grotesquely mismatched. What could be further apart than Stalinist Moscow and an English country farmyard?

He cared passionately for the English countryside, and lived there in the late 1930s, keeping a village shop, a goat and a notebook. Animal Farm overflows with lovingly observed physical detail of country life. But then, from the mouth of the pig Major, there erupts a perfect parody of a communist speech: the fruit of many hours Orwell had spent poring over the political pamphlets he collected. Only he would have this peculiar combination of expertises. Only Orwell would know both how to milk a goat and how to skewer a revisionist.

The twists and turns of his animal regime closely follow the decay of the Russian revolution into tyranny. There is no ambiguity here: the pig Napoleon is Stalin, the pig Snowball is Trotsky. And there is his humour, an underrated part of Orwell’s sandpapery charm. (Soon after he was shot through the neck in Spain, his commanding officer perceptively reported: “Breathing absolutely regular. Sense of humour untouched.”) Unforgettable is that perfect one-liner, at once comic and deeply serious: “All Animals Are Equal, But Some Animals Are More Equal Than Others”.

Animal Farm is a timeless satire on the central comi-tragedy of all politics — that is, the comi-tragedy of corruption by power. This ability to move from the particular to the universal also characterises his essays: the other genre in which he wrote best about politics.

What he abhors, perhaps even more than violence or tyranny, is dishonesty. Marching up and down the frontier between literature and politics, like a sentry for morality, he can spot a double standard at 500 yards in bad light. Does a Tory MP demand freedom for Poland while remaining silent about India? Sentry Orwell fires off a quick round.

Orwell the moralist is fascinated by the pursuit not merely of truth, but of the most complicated and difficult truths. It starts already with the early essay Shooting an Elephant, where he confidently asserts that the British empire is dying but immediately adds that it is “a great deal better than the younger empires that are going to supplant it”. At times, he seems to take an almost masochistic delight in confronting uncomfortable truths.

Not that his own political judgment was always good. His vivacious and perceptive wife Eileen wrote that he retained “an extraordinary political simplicity”. There are striking misjudgments in his work. It’s startling to find him, early on, repeating the communist line that “fascism and capitalism are at bottom the same thing”.

He opposed fighting Hitler until well into 1939, only to reverse his position. In his wartime tract The Lion and the Unicorn: Socialism and the English Genius, he proposes the nationalisation of “land, mines, railways, banks and major industries”. Orwell was a very English writer, and we think of understatement as a very English quality. But his speciality is outrageous overstatement: “No real revolutionary has ever been an internationalist,” “All leftwing parties in the highly industrialised countries are at bottom a sham,” “A humanitarian is always a hypocrite.”

As VS Pritchett observed, in reviewing The Lion and the Unicorn, he “is capable of exaggerating with the simplicity and innocence of a savage”. But that is what satirists do. Evelyn Waugh, from the other end of the political spectrum, did the same. So this weakness of his non-fiction is one of the great strengths of his fiction.

Both his life and his work are case studies in the demands of political engagement. In Writers and Leviathan he describes the political writer’s dilemma: “seeing the need of engaging in politics while also seeing what a dirty, degrading business it is”. After briefly being a member of the Independent Labour party, he concludes that “a writer can only remain honest if he keeps free of party labels”. That keyword “honest” again. But he plans and becomes vice-chairman of a non-party organisation called the Freedom Defence Committee, defending freedom against imperialism and fascism, of course, but now, above all, against communism.

A word is due about the already notorious list of crypto-communists and fellow travellers which he is popularly thought to have handed over to the British secret service. (”Socialist icon who became an informer,” trumpeted the Daily Telegraph when “breaking” the story in 1998.) The facts are these. Orwell kept a pale blue notebook in which he noted names and details of suspected communist agents or sympathisers. The content of this notebook is disquieting, with its sharp judgments — “almost certainly agent of some kind”, “decayed liberal”, “appeaser only” — and especially its national/racial annotations: “Jewish?” (Charlie Chaplin) or “English Jew” (Tom Driberg) as well as “Polish”, “Jugo-Slav”, “Anglo-American” and so on. There is something unsettling — a touch of the old imperial policeman — about a writer who could have lunch with a friend like the poet Stephen Spender and then go home to note “Sentimental symphathiser and very unreliable. Easily influenced. Tendency to homosexuality.”

However, two very important things need to be said in explanation. First, there was a cold war on. There were Soviet agents and sympathisers about, and they were influential. The most telling example is the man Orwell had down as “almost certainly agent of some kind”. His name was Peter Smollett. During the second world war he was the head of the Russian section in the Ministry of Information, and it was on his advice that TS Eliot, no less, rejected Animal Farm for Jonathan Cape. We now know that Smollett was indeed a Soviet spy.

Second, Orwell did not give this notebook to the British secret service. He gave a list of 35 names drawn from it to the Information Research Department, a semi-secret branch of the Foreign Office which specialised in getting writers on the democratic left to counter the then highly organised Soviet communist propaganda offensive. Absurdly, the British government has not declassified this list and any letter that accompanied it. So we still don’t know exactly what Orwell did. But from the available evidence it is quite clear that Orwell was not putting some British thought police on to these people’s tails. All he was doing, in effect, was to say: “Don’t use these people for anti-communist propaganda because they are probably communists or communist sympathisers!”

A dying man, but still in complete command of his faculties, Orwell judged this to be a morally defensible act for a writer in a period of intense political struggle, just as he had earlier judged that it was proper for a politically engaged writer to take up arms against Franco. I think he was right. You may think he was wrong. Either way, he exemplifies for us — he is that exemplar — of the dilemmas of the political writer.

Finally, of course, Orwell’s list, and Orwell’s life, are much less important than the work. It matters, to be sure, that there is no flagrant contradiction between the work and the life — as there often is with political intellectuals. The Orwellian voice, placing honesty and single standards above everything, would be diminished. But what endures is the work.

If I had to name a single quality that makes Orwell still essential reading in the 21st century, it would be his insight into the use and abuse of language. If you have time to read only one essay, read Politics and the English Language. This brilliantly sums up the central Orwellian argument that the corruption of language is an essential part of oppressive or exploitative politics. “The defence of the indefensible” is sustained by a battery of euphemisms, verbal false limbs, prefabricated phrases, and all the other paraphernalia of deceit that he pinpoints and parodies.

The extreme, totalitarian version that he satirised as Newspeak is less often encountered these days, except in countries such as Burma or North Korea. But the obsession of democratically elected governments, especially in Britain and America, with media management and “spin” is today one of the main obstacles to understanding what is being done in our name. There are also distortions that come from within the press, radio and television themselves, partly because of hidden ideological bias but increasingly because of fierce commercial competition and the relentless need to “entertain”.

Read Orwell, and you will know that something nasty must be hidden behind the euphemistic, Latinate phrase used by Nato spokesmen during the Kosovo war: “collateral damage”. (It means innocent civilians killed.) Read Orwell, and you will smell a rat whenever you find a British newspaper or politician once again churning out a prefabricated phrase such as “Brussels’ inexorable march to a European superstate”.

He does not just equip us to detect this semantic abuse. He also suggests how writers can fight back. For the abusers of power are, after all, using our weapons: words. In Politics and the English Language he even gives some simple stylistic rules for honest and effective political writing. He compares good English prose to a clean window pane. Through these windows, citizens can see what their rulers are really up to. So political writers should be the window cleaners of freedom.

Orwell both tells and shows us how to do it. That is why we need him still, because Orwell’s work is never done.