Guardian: An underground theatre group is shining a light on the tyranny that rules in Belarus

Like Gavel and Kundera Belarusian Free Theatre are bravest critics of Belarus's rotting Brezhnevian state.

The Belarus Free Theatre arrived in London last week and seemed to take us from the 2010s to the 1970s. Everything was as it had been in the cold war. Just as Havel and Kundera came to speak for oppressed Czechs, so the actors from Europe's last dictatorship are the most prominent and bravest critics of Belarus's rotting Brezhnevian state. Just as Tom Stoppard was a friend to east European dissidents during communism, so he is a friend to Belarussia's underground artists today. Following tradition once more, Stoppard welcomed them to Britain on behalf of Index on Censorship, which Stephen Spender created in 1972 to speak for persecuted Soviet writers.

Ironic asides, which so many artists deployed to survive and subvert communism, peppered my conversation with Natalia Koliada, the theatre's founder and a woman with the relaxed courage of a committed democrat who accepts the risk of persecution. She tells the grim story of how the secret police have threatened her husband and forced her company to perform in bars or private houses or in the woods before an audience she must vet to ensure it does not contain informers, and then pulls herself up short. A grin breaks out on her elfin face and she declares: "Our dictator still calls our secret police the KGB. At least he's honest about that."

They met Harold Pinter just before he died and he thundered that the Belarussians had to realise Britain under Tony Blair was a kind of dictatorship as well. Members of the company patiently explained the realities of everyday life in Belarus and even the grudging Pinter had to admit that maybe the British state was not so bad after all.

One of the first plays the company tried to perform was 4.48 Psychosis, by Sarah Kane, a wrenching dramatisation of suicide and depression, which are at extraordinary high levels in Belarus. The censor was in a quandary. He knew perfectly well why the Free Theatre wanted to stage the play. But as a functionary of Alexander Lukashenko's dictatorship, he could not admit that mental illness depresses the subject population.

"You can't show it because there is no depression in Belarus," he explained.

"We're not saying there is," replied the ingenious actors. "Sarah Kane was British, so if any government is being criticised it is the British government."

The censor was stumped but rallied with: "Ah, but people who see the play may think that there is depression in Belarus – even though there isn't – so I'm still banning it."

I went to Index on Censorship out of sense of duty, yet the company's performance isn't worthy but an inventive combination. Depictions of misery are leavened with flashes of Auden's "ironic points of light". Numbers, which you can see on the Index website, has the actors miming surreal routines while a cameraman projects on to the wall the statistics that enumerate Belarus's plight: the scale of the sex trade in young women; the botched abortions which leave women sterile; the poverty of a country where the average wage is $350 a month; and the oppression of a state which murders its political opponents and has the fourth highest prison population per capita in the world. Then, to illustrate how Belarussians are desperate to emigrate, the projector flashed up the story of how, in October 2006, 240 cows trampled down an electric fence and swam the River Bug to sanctuary in Poland, the first case of mass flight to freedom by livestock in the EU's history, as the company delightedly points out.

The danger for outsiders who enjoy the ironic style of the opponents of a dictatorship is that our pleasure can topple over into an acceptance of tyranny. Although British theatre has shown admirable solidarity with Belarussian dissidents – not only Stoppard and Pinter, but the Soho, West Yorkshire and Almeida theatres have promoted their work – most people couldn't find Belarus on the map. Many of those who can regard the continuing survival of Soviet oppression in a small state on Europe's borders as an anachronism that is so far removed from the main currents of modernity it is almost quaint.

Yet contrary to the supposedly "realist" school of foreign policy so beloved by our Foreign Office, dictatorships are not stable regimes. They are always on the move, heading towards greater repression or collapse. Nor are they any less modern than other forms of government. Both the Free Theatre actors and the organisers of the Charter 97 website, which monitors Belarussian tyranny, told me how sinister they found Lukashenko's new alliances. He is a member of the 21st-century's club of dictators, which, in a break with the patterns of the cold war, brings socialist tyrannies together with the promoters of radical reaction. The alliance of the red and brown, the communistic and fascistic, meant that while Hussein and Milosevic were alive, Lukashenko was their friend. Now he allies with Iran's messianic Islamist dictatorship. As he gets more senile, he picks fights with his former protectors in Moscow and turns towards his new allies for ideas.

He will hold elections in the winter and, as in Iran, they will be rigged. Following Ahmadinejad's example, he is preparing to demoralise opposition by controlling the internet. New laws force website owners to register with the state and service providers to identify users and map their browsing history. Dissident sites, already subject to denial of service attacks, presumably organised by state security, face being blacklisted.

If a fake poll provokes protests, few imagine that he won't imitate Iran again and set his thugs on his opponents. He has already authorised the murder of political opponents and the beating of opposition journalists and artists; there's no reason why he wouldn't go further.

Recently, Natalia Koliada asked an EU diplomat why there was so little political or media interest about oppression in Europe's backyard. He replied that Europe would not get agitated until bodies piled up in the streets.

Or, to put it another way, if you know nothing about Belarus, you may learn more than you wanted to know soon and for all the wrong reasons.