Mohammed will take to the streets today, come what may. He is among the first of 2,000 unsuspecting pioneers – youths who signed up to the Facebook event that brought thousands of anti-government protesters to the streets.

Today, as citizens gather for Friday prayers, is expected to be the biggest day in the movement to oust the Egyptian president, Hosni Mubarak, from his 30-year rule. It may also be the most dangerous.

"If the police react violently this time, many people will be killed," says Mohammed. "But people now believe in change, they want Egypt to be a better place. They are afraid of what will happen, but they won't change. They will go."

In Cairo and Suez, violence flared as Egyptian security forces used tear gas, rubber bullets and water cannon against the crowds. Over 1,000 protesters have been carted away, many beaten; seven so far are reported dead.

The atmosphere in Cairo is tense. Anti-riot vans patrol the boulevards. Armoured trucks stand parked near flashpoints in the city, and amin dowla – plain-clothes officers from the state security service – are everywhere.

Public gatherings have been banned. A football match was cancelled Thursday for fear of violence.

By Tuesday, more than 90,000 people had signed up to the Facebook event. This time around it looks set to be much bigger. "One social media outlet rallying people to the street has 381,000 supporters at the last count," says Hisham Kassem, a respected independent editor.

The main actors of the past few days are well-educated people, middle-class students. Critics have commented that this group remains a tiny minority of Egypt's population.

Mohammed fits the profile, but this protest is bringing together people from different social backgrounds, he says. "I went to the elections, to other events. But now, I am going to the protests with people who have never been before. There are people from all other backgrounds. I know factory workers who went and got beaten, but they and their friends are going again."

Unemployment levels among Egypt's youth are deplorable. It is estimated that 25 per cent of men and 59 per cent of young women are without work. If the poor choose to join the intellectual classes, the riots could reach a critical mass.

Driving a beaten-up vehicle through Cairo's streets, Raman, a taxi driver, smiles a crack-toothed grin. "Friday there will be huge riots. Everyone is going to take part," he says.

Professor Abdallah Alashaal was an employee in the Egyptian government's foreign ministry. Now he is a well-known figure of opposition. "This is a velvet revolution; it is an uprising of the youth," he says.

"There is a sense of anticipation and emancipation here. The people in the street are not ideologised: they are not Christians, Muslims, Marxists. They are Egyptians. It is not a political movement."

In a dark backstreet, away from the main roads lined with security, a key protest organiser meets me, eyes shifty, watching out for plain-clothes police. He is right to be afraid. Egypt has a bad record on torture. His activities are risking his life.

He walks beside me, talking in a low voice. "We don't need help, this is not organised by anyone outside. We are motivated by Tunisia, but this is Egyptians acting for Egyptians." He disappears round a corner and his phone cuts off as he changes his sim card, again.

The outcome of Friday's events and the actions of the security forces remains unknown. "I can't see that anybody can predict what [will happen] tomorrow or days to come. In a few days it could be over. It could also get bigger and bigger and at last with the military participating," says Kassem.

Even key participants don't believe that it will bring about the collapse of Mubarak's regime immediately. "Mubarak won't leave peacefully; his government is much stronger than Tunisia's," says Mohammed.

But experts agree that, even if today is followed by apparent calm, the political situation in Egypt has changed. "It has weakened the regime," says Alashaal. "They didn't expect that the Egyptian population can rise up like this."

This popular revolt is unprecedented in Mubarak's strong-handed rule. "Even with nothing else, we have already achieved history," Mohammed says.