Robert Fisk: Week 3, day 16, and with every passing hour, the regime digs in deeper

Our writer sees Cairo's protesters rally again in Tahrir Square

Blood turns brown with age. Revolutions do not. Vile rags now hang in a corner of the square, the last clothes worn by the martyrs of Tahrir: a doctor, a lawyer among them, a young woman, their pictures strewn above the crowds, the fabric of the T-shirts and trousers stained the colour of mud. But yesterday, the people honoured their dead in their tens of thousands for the largest protest march ever against President Hosni Mubarak's dictatorship, a sweating, pushing, shouting, weeping, joyful people, impatient, fearful that the world may forget their courage and their sacrifice. It took three hours to force our way into the square, two hours to plunge through a sea of human bodies to leave. High above us, a ghastly photomontage flapped in the wind: Hosni Mubarak's head superimposed upon the terrible picture of Saddam Hussein with a noose round his neck.

Uprisings don't follow timetables. And Mubarak will search for some revenge for yesterday's renewed explosion of anger and frustration at his 30-year rule. For two days, his new back-to-work government had tried to portray Egypt as a nation slipping back into its old, autocratic torpor. Gas stations open, a series of obligatory traffic jams, banks handing out money – albeit in suitably small amounts – shops gingerly doing business, ministers sitting to attention on state television as the man who would remain king for another five months lectured them on the need to bring order out of chaos – his only stated reason for hanging grimly to power.

But Issam Etman proved him wrong. Shoved and battered by the thousands around him, he carried his five-year- old daughter Hadiga on his shoulders. "I am here for my daughter," he shouted above the protest. "It is for her freedom that I want Mubarak to go. I am not poor. I run a transport company and a gas station. Everything is shut now and I'm suffering, but I don't care. I am paying my staff from my own pocket. This is about freedom. Anything is worth that." And all the while, the little girl sat on Issam Etman's shoulders and stared at the epic crowds in wonderment; no Harry Potter extravaganza would match this.

Many of the protesters – so many were flocking to the square yesterday evening that the protest site had overflowed onto the Nile river bridges and the other squares of central Cairo – had come for the first time. The soldiers of Egypt's Third Army must have been outnumbered 40,000 to one and they sat meekly on their tanks and armoured personnel carriers, smiling nervously as old men and youths and young women sat around their tank tracks, sleeping on the armour, heads on the great steel wheels; a military force turned to impotence by an army of dissent. Many said they had come because they were frightened; because they feared the world was losing interest in their struggle, because Mubarak had not yet left his palace, because the crowds had grown smaller in recent days, because some of the camera crews had left for other tragedies and other dictatorships, because the smell of betrayal was in the air. If the Republic of Tahrir dries up, then the national awakening is over. But yesterday proved that the revolution is alive.

Its mistake was to underestimate the ability of the regime to live too, to survive, to turn on its tormentors, to switch off the cameras and harass the only voice of these people – the journalists – and to persuade those old enemies of revolution, the "moderates" whom the West loves, to debase their only demand. What is five more months if the old man goes in September? Even Amr Moussa, most respected of the crowds' favourite Egyptians, turns out to want the old boy to carry on to the end. And woeful, in truth, is the political understanding of this innocent but often untutored mass.

Regimes grow iron roots. When the Syrians left Lebanon in 2005, the Lebanese thought that it was enough to lop off the head, to get the soldiers and the intelligence officers out of their country. But I remember the astonishment with which we all discovered the depth of Syria's talons. They lay deep in the earth of Lebanon, to the very bedrock. The assassinations went on. And so, too, it is in Egypt. The Ministry of Interior thugs, the state security police, the dictator who gives them their orders, are still in operation – and if one head should roll, there will be other heads to be pasted onto the familiar portrait to send those cruel men back into the streets.

There are some in Egypt – I met one last night, a friend of mine – who are wealthy and genuinely support the democracy movement and want Mubarak to go but are fearful that if he steps now from his palace, the military will be able to impose their own emergency laws before a single reform has been discussed. "I want to get reforms in place before the man leaves," my friend said. "If he goes now, the new leader will be under no obligation to carry out reforms. These should be agreed to now and done quickly – it's the legislature, the judiciary, the constitutional changes, the presidential terms that matter. As soon as Mubarak leaves, the men with brass on their shoulders will say: 'It's over – go home!' And then we'll have a five-year military council. So let the old man stay till September."

But it's easy to accuse the hundreds of thousands of democracy protestors of naivety, of simple-mindedness, of over-reliance on the Internet and Facebook. Indeed, there is growing evidence that "virtual reality" became reality for the young of Egypt, that they came to believe in the screen rather than the street – and that when they took to the streets, they were deeply shocked by the state violence and the regime's continued, brutal, physical strength. Yet for people to taste this new freedom is overwhelming. How can a people who have lived under dictatorship for so long plan their revolution? We in the West forget this. We are so institutionalized that everything in our future is programmed. Egypt is a thunderstorm without direction, an inundation of popular expression which does not fit neatly into our revolutionary history books or our political meteorology.

All revolutions have their "martyrs", and the faces of Ahmed Bassiouni and young Sally Zahrani and Moahmoud Mohamed Hassan float on billboards around the square, along with pictures of dreadfully mutilated heads with the one word "unidentified" printed beside them with appalling finality. If the crowds abandon Tahrir now, these dead will also have been betrayed. And if we really believe the regime-or-chaos theory which still grips Washington and London and Paris, the secular, democratic, civilized nature of this great protest will also be betrayed. The deadly Stalinism of the massive Mugamma government offices, the tattered green flag of the pathetic Arab League headquarters, the military-guarded pile of the Egyptian Museum with the golden death mask of Tutankhamen – a symbol of Egypt's mighty past – buried deep into its halls; these are the stage props of the Republic of Tahrir.

Week three – day sixteen – lacks the romance and the promise of the Day of Rage and the great battles against the Egyptian Ministry of Interior goons and the moment, just over a week ago, when the army refused Mubarak's orders to crush, quite literally, the people in the square. Will there be a week six or a day 32? Will the cameras still be there? Will the people? Will we? Yesterday proved our predictions wrong again. But they will have to remember that the iron fingernails of this regime have long ago grown into the sand, deeper than the pyramids, more powerful than ideology. We have not seen the last of this particular creature. Nor of its vengeance.