DURING a Persian new year’s party (in late March) at Iran’s flagship South Pars project in the Persian Gulf, where the world’s largest known gasfield is being tapped, a labourer called on Iran’s workers to unite. Behnam Khodadadi demanded better pay and conditions, and a proper trade union. Around 1,500 workers stopped security guards from detaining Mr Khodadadi. A week later he was fired from his job at Iran Industrial Networks Development, a contractor for the state-owned National Iranian Oil Company. Mr Khodadadi may have been muzzled, but disaffection is growing among Iranian workers as inflation outpaces wage rises and workers are laid off. At the same time attempts to organise labour are being suppressed in the run-up to June’s presidential elections.

“They haven’t paid us for at least four months and I have to keep borrowing money,” says Jamshid, a 32-year-old industrial worker in Tehran, the capital. Last month the minimum wage was raised by 25%, to 4.87m rials ($140) a month, but even by official criteria this is one-third of what is deemed to be a living wage in the capital. The drop in the rial’s value means that, when it comes to the imports on which Iran relies, Iranian cash is worth barely a third of what it was in 2011, before the United States imposed sanctions on the country’s financial system.

Iran does not recognise independent unions, so workers have to make do with Islamic Labour Councils, which must be approved by employers and the security services. Reckoning that these councils are in cahoots with the government, workers tend to keep their grievances to themselves for fear of being sacked as troublemakers. Labour leaders are often imprisoned.

Ali Nejati and Reza Shahabi, who led sugarcane workers’ and bus drivers’ unions respectively, were recently freed under surveillance. Mr Shahabi is now in prison again, as is Muhammad Jarahi, who stands for petrochemical workers, and Shahrokh Zamani, a painter, all of them guilty of “endangering national security”. “Not having independent workers’ unions guarantees things will stay the same,” Mr Nejati recently told an Iranian radio station based in Germany. “As a workers’ representative I complained and I went to prison for it and was fired.”

Despite the long history of Iran’s labour movement and the big part its oil workers played in deposing the shah in 1979, Iran’s workers have witnessed a steady erosion of their bargaining power. After the revolution, independent workers’ councils won rights to such things as a 40-hour week and lodging allowances. They got rid of people who had worked for the shah’s intelligence service. But during the Iran-Iraq war (1980-88) the unions’ independence was destroyed. Under President Akbar Hashemi Rafsanjani and his successor, Muhammad Khatami, imports soared while Iran’s own manufacturing industry slumped. Unions have been further weakened by the reclassification of many workers as temporary.

Last month several bakers were arrested for allegedly organising their colleagues in the Kurdish city of Sanandaj. At the same time, workers at a tractor-making company in Tabriz, in the north-west, signed a letter accusing managers of “brutal treatment, intimidation and failing to pay wages”. “Authorities who always talk about justice in the Islamic republic should know that complete injustice prevails in this system,” they wrote.

“We are at the mercy of our employers,” says Mahmud, a Tehran street sweeper on his night shift, scraping rubbish out of an open gutter with a coarse wicker brush. “We almost never get the overtime pay we are entitled to but we can’t complain because we would be fired.” A senior municipal worker admits that thousands of non-unionised street sweepers, who clean the capital by night, often go months without pay. Last year the office of Muhammad Qalibaf, Tehran’s mayor and a presidential hopeful, commissioned a film called “Those Who Wear Orange” about a brainy university graduate who becomes a street cleaner—for love of the job.