Ansari broke the silence. ‘I must respectfully disagree with the honourable President. I say that many complaints remain – and they are not fanciful at all.’

It was a simple observation, but the response was electric; the shouting and applause went on for at least a minute. If the announcement of Jabari’s resignation had been timed to puncture the mood of the demonstration, that had been badly misjudged; instead, it had given everyone in the crowd a chance to affirm, with the vocal support of their fellow malcontents, that the momentum of the uprising was undiminished.

The organiser took the microphone and began giving detailed instructions for the march. After reminding everyone of the route, he added, ‘Most importantly, please obey the marshals wearing green sashes.’ Martin looked around and located a woman a few metres away, only now draping a broad strip of green fabric across one shoulder of her brown manteau.

They began to move north, towards Jomhuri-ye-Eslami Avenue. The marchers wouldn’t expect any help from the traffic police, but the protest had been publicised well enough to deter most drivers from the route, and in any case, sheer force of numbers gave the pedestrians right of way. The density of the crowd kept their pace to a shuffle, and the afternoon heat was beginning to bite, but the atmosphere was upbeat, and the constant rhythmic chant of ref-eren-doom – the English loan-word imported virtually unchanged into Farsi – was echoed playfully between different groups, breaking up the monotony and sparing people’s throats.

Jomhuri-ye-Eslami Avenue was a broad, elegant street, with a stately row of fountains where it met Baharestan Square. It had been spared from the current spate of road-works that plagued much of central Tehran – all the flyovers and tunnels-in-progress that filled the streets with concrete dust, coating Martin’s trouser cuffs and shredding his nasal membranes. Some of the upmarket clothing shops along the route were closed and shuttered, but others had banners of support in the windows, and a few had proprietors, sometimes even whole families, standing in the doorways waving and cheering. Martin thought back to 2003, when he and Liz had joined an anti-war march through Sydney, just before the invasion of Iraq. Given the outcome, that was hardly an encouraging comparison, but he wasn’t reaching for a political analogy. It was simply that the measured, determined mood of the crowd, the steady rhythm of their advance, the whole texture of sounds and emotions, had been cut from the same cloth.

Martin felt a sudden ache of loneliness; he could not have expected Liz to be marching beside him here, but it would have been enough to be able to sit with her in the evening and say: You know what I was reminded of today? Now their shared memories meant nothing.

‘Did you see that?’ Behrouz asked him.

‘Sorry, I was-’

‘Her phone.’ Martin followed his gaze; the green-sashed marshal was using it to talk to someone. Martin checked his own phone; there was still no signal.

‘Do you want to ask her about it?’ Martin suggested. ‘If you can convince her we’re not informers.’

When she’d finished the call Behrouz approached her and made introductions. The woman gave her name as Mahnoosh.

She addressed Martin directly, in English. ‘I read some of your stories before they cut the internet.’

Martin felt a twinge of self-consciousness; his reports were written for Australian readers skimming half-a-dozen foreign political stories over breakfast, not sophisticated Tehranis in the thick of the action. He said, ‘I hope you’ll excuse any mistakes I made; I’ve only been here a few months.’

She smiled slightly. ‘Of course.’

‘Do you mind if I ask you how your phone’s working?’

‘It’s not going to the towers,’ she said. ‘Just direct to other phones.’

‘I don’t understand.’

She spoke with Behrouz. ‘We’ve set up a mesh network,’ he translated. ‘It doesn’t rely on any infrastructure from the phone company; the phones just pass the data between themselves. Email, text messages, voice calls, web services.’

Martin was impressed. No doubt the government would soon find a way to block the system – they were already jamming satellite TV – but for now the protesters had an unexpected advantage. ‘Can I plug into this network?’

Mahnoosh held out her hand and he passed her his phone. She inspected it for a few seconds then returned it. ‘Sorry, no. The best one is this-’ She took her own phone from her pocket and showed it to him. The manufacturer’s logo was one he’d never seen before: a triangle formed from three copies of the letter S.

‘Who makes these?’

‘Slightly Smart Systems,’ Mahnoosh replied, a hint of amusement in her eyes at the wonderfully self-deprecating name. ‘Indian software, Chinese hardware. But we made some changes ourselves.’

Martin handed the phone back. He was surprised that Omar hadn’t tried to sell him one, knowing how useful it would be. But since the night of the crash they’d been more circumspect in their dealings with each other; when Sandra Knight broke Shokouh’s story in Paris she’d kept Martin right out of the picture, but the authorities would automatically have stepped up their surveillance of all foreign journalists.

They passed Cinema Europa, then Cinema Hafez. The Iranian stars gazed down coolly from their billboards, offering neither encouragement nor disapproval. Ahead of the marchers, a long stretch of asphalt was utterly deserted, empty of cars as far as the eye could see; even with the chanting crowd around him, Martin had a moment of end-of-the-world goose-flesh. Police were following the march, but they remained at the edges and he hadn’t seen them administer so much as a provocative shove. Perhaps the authorities had decided to allow people to let off steam, unmolested, in one last show of defiance before Jabari’s resignation was used to draw a line under everything that had come before.

Martin and Behrouz moved through the crowd, gathering quotes. ‘Jabari’s resignation means nothing,’ one man opined. ‘It won’t bring down rents. It won’t give my son a job.’

‘But how would a referendum help the economy?’ Martin pressed him.

‘Not quickly,’ the man conceded. ‘But it would open the door to different ideas, not the same group holding power year after year. The hardliners call everyone else un-Islamic, but Ansari is not un-Islamic. I asked him myself, would he ban the headscarf in some places, like they do in Turkey. He said no, it’s up to each woman if she wants to wear it or not.’

Other people expressed similar views. They were tired of the stale, self-perpetuating clique that clung to power by wrapping itself in claims of piety. If throwing out the veto powers of the Guardian Council – or abolishing the Council entirely – was the only route to change, so be it. The voters themselves were perfectly capable of rejecting candidates who would harm the nation; as one woman put it, ‘We aren’t infants who need the bones picked out of our food.’

‘Rast! Injaa rast!’ Mahnoosh shouted urgently, raising her arms and gesturing. Right, here! She was steering the march off Jomhuri-ye-Eslami, into a side-street. She was not especially tall, but her voice carried, and her instructions were heeded and echoed back through the ranks. As the crowd squeezed into the narrower road Martin approached her.

‘What’s happening? I thought we were going straight to Ferdowsi Street.’

Mahnoosh held up her phone, displaying an image of a train-carriage packed with militia, some of them carrying guns. A sign on the platform beside the carriage said Imam Khomeini Station – one stop south of Sa’di Station. If the marchers stuck to their original route, they would be approaching Sa’di Station just as the armed Basijis emerged from the Metro.

Martin exchanged a glance with Behrouz; did they want to break from the march and check out Sa’di? Martin was tempted, but then decided it was better to stay with the crowd and see how they fared.