In the second week of December 1978, between 1 and 2 million people marched peacefully through Tehran calling for the Shah to leave. Around a fifth to almost a half of the city’s population was on the streets. The CIA, warily watching opposition in a key regional ally and client for US arms, noted that one man was “the focal point”, providing “guidance and support for the movement acting in his name in Iran”. This was the Ayatollah Ruhollah Khomeini, then thousands of miles away in exile in Paris, though his portrait was carried by many of the marchers. Decades later and the regime established by Khomeini is still in power in Iran. Crowds are on the streets again in Tehran and other Iranian cities following the death on 16 September of 22-year-old Mahsa Amini, arrested by the morality police, who accused her of breaking laws on wearing the hijab introduced by Khomeini’s regime in 1981. Women have thrown headscarves on to fires, vast posters celebrating the regime have been torn down, police stations torched. The unrest appears set to intensify. Could this finally be the spark that leads to massive change in Iran, as many hope? Some believe a fuse has been lit. Oppression of women is an existential issue for the regime, but perhaps, too, a fundamental weakness. The powerful and impressive images coursing through our Facebook and Twitter feeds, and reproduced by mainstream media, might lead us to believe they are right. Is history repeating itself? Certainly some protesters have invoked parallels with the tumultuous events of 1979, chanting :“Death to the oppressor, be it the shah or the supreme leader!” There are many reasons to be impressed by what is happening in Iran. Protests on this scale prompted by anger over the abuse of women’s rights are rare anywhere. Men are on the streets, too, and those involved in the unrest are reported to be more demographically diverse than participants in similar events in recent years. No one can doubt that the protests are also tapping into wells of deep discontent with the manifest economic, political and moral failures of the repressive theocratic regime. But we may be letting our hopes run ahead of reality. What we are seeing is very far from being a full picture of events. Reporting from the ground is extremely limited. After a decade or so of exposure to the extraordinary impact of contemporary media technology, we have seen again and again how a single clip uploaded from an individual’s mobile phone can be broadcast to hundreds of millions through social media, then further amplified by mainstream media. We see something that is happening in one street in one town in one province – but that is not always representative of events across a vast and populous country. In Iran now, it’s difficult to work out exactly how extensive the unrest is. Journalists, academic experts and government intelligence analysts will seek to supplement inadequate visual evidence, but their conclusions very often have little impact compared with emotive images. Populist politicians know this, so do terrorists of every ideology and creed. We prefer to believe what we want to be true. Forty-three years ago, the Shah was ousted not just by Khomeini and his clique of radical clerics, but by a broad coalition of opposition groups, which mobilised diverse constituencies: secular urban liberals, old-school communists, new left fedayeen, Islamo-Marxist guerrillas and nationalists who venerated the memory of Mohammed Mosaddegh, the prime minister deposed in 1953 in a coup backed by the US and Britain. There were also the young men from the sprawling new shanty towns on the outskirts of Iranian cities or from the provinces who provided the shock troops of the radical clerics and who now, grown old, cling to the power they won back then. Witnesses of the unrest in Iran in 1978 and 1979 included Rzyard Kapuściński, the celebrated Polish journalist, who described one massive march in Tehran as “a human river, broad and boiling, flowing endlessly, rolling through the main street from dawn till dusk. A flood, a violent flood that in a moment will engulf and drown everything.” The crowd took eight hours to pass through the city centre. There is no Kapuściński in Tehran now and we can be fairly sure there are no eight-hour marches either. The harsh truth is that though these are important protests, they are likely to be crushed by the still powerful regime. Our excitement at the stirring images we see of demonstrations not only often leads us to exaggerate the breadth and depth of a protest movement, particularly when those on the streets appear to share many of our own values and aspirations, but also to underestimate the strength of their enemies, too. Those ranged against those now protesting in Iran are still very formidable indeed. The problem of interpreting far-off events is evidently not a consequence merely of smartphones and the internet. The Iranian revolution of 1979 was covered by hundreds of reporters from all over the world. In the few months that Khomeini was in Paris before his return to Tehran, he granted 150 interviews. Even hard-bitten hacks were taken in by Khomeini’s words about democracy, women’s rights and tolerance. The US ambassador in Tehran decided the statesman whom Khomeini would most resemble after taking power was Gandhi. Within two years of taking power, Khomeini had ruthlessly eliminated almost all opposition, filled prisons and introduced the laws that imposed the hijab on women. But the ubiquity of news today, how it reaches us and how it is consumed, and the primacy granted to the image by technology brings a particular risk. The passage of information is often described as a flow, which implies something continuous, steady, rhythmic. In reality, it is utterly choppy and irregular and as we work to build what we hear and see into something with sufficient unity to make sense, we fill the many gaps ourselves. Some deploy prejudices and fear, creating elaborate conspiracy theories. Others complete the incomplete picture with dreams and hopes, a more positive reaction to be sure but also one that can do harm. This does not mean that those on the streets in Iran are not to be admired and their example celebrated. But that when we think of how we can help and support them, we should be careful to do so with eyes that are clear, not clouded by false optimism. This will make our support even be more valuable.