EighT feet tall and crowned with coils of barbed wire, the concrete barrier slices Mohammed Mahmoud Street in two.

On one side, desert tanks and khaki-clad Egyptian troops guard the rubble-strewn streets leading to the Ministry of the Interior. Across the ad hoc wall, a band of red-jacketed volunteers keep members of an enraged crowd from clambering over and avenging six days of bloodshed that have claimed 41 lives and injured thousands.

“Peaceful! Peaceful!” goes the chant. For now it holds.

It is on this precarious frontier – built by military police early on Thursday morning – where Egypt’s political crisis finds its starkest, most tangible expression: a face-off between defiant protesters and a military government that has continued all the worst practices of the Mubarak regime it helped oust in February.

Last week’s events in Cairo have been dubbed Egypt’s second revolution. But for most protesters tying to topple Field Marshal Hussein Tantawi, it’s a direct continuation, one that aims to finally bring an end to six decades of military-backed dictatorship and seize the kind of accountable democracy the army seems unable or unwilling to grant.

Parliamentary elections starting tomorrow were supposed to speed the country’s democratic transition. But rising opposition to the military council, which has tightly managed the electoral and constitutional process to safeguard the army’s dominance, is pulling the entire process into turmoil.

Just a half mile from Mohamed Mahmoud Street, Cairo’s Tahrir Square is once again home to a mass sit-in. Dozens of tents crowd the muddy gardens while military helicopters circle the skies. Every hour another march converges on the square, negotiating a thick web of civilian checkpoints and swelling the tense crowd.

As Friday prayers broke, more than 100,000 protesters thronged the square. After months of division, they were finally united by a single, clear demand: Egypt’s rulers must go – and long before the June 2012 date promised for presidential elections. Omar Hashem, a 33-year-old tour guide from Alexandria camped on the square, said: “Who controls Tahrir controls Egypt – it is only a matter of time. Tantawi is a mini-Mubarak, he doesn’t have the revolution in his blood. We were suspicious from the start but we gave the army a chance. They’ve failed and just brought more killing and misery.”

With protests spread from Aswan to Alexandria, multiple political parties withdrawing from the race, and mounting concerns over security, a low election turnout looks increasingly likely. Should that happen, few will judge the results legitimate.

“This is Egypt’s most important election in 50 years, it’s meant to produce a constitution that’s a building block for our future,” said Mohamed Aboud, 28, a sales manager from Giza. “But under a corrupt military council it will be meaningless. Who would ever trust what comes from them now?”

Aboud was one of many who rushed to Tahrir last Saturday evening, just hours after central security forces dispersed a small-scale sit-in crammed on a single traffic island.

It was the spark that ignited a groundswell of seething anger against the military, which has been simmering for the last nine months. The military has already amassed an unsavoury record for smashing protests and jailing and torturing thousands of dissidents. An Amnesty International report last week unfavourably compared the junta’s human rights record with that of the Mubarak regime.

Crucially – and for the first time in months – anti-military protesters found popular support. As security forces lashed out at a second and much larger protest last Sunday, live coverage fuelled fresh indignation. One particular image of riot police dumping a young man’s body on a rubbish pile on the edge of Tahrir outraged ordinary Egyptians who hadn’t taken to the streets since spring.

What followed were several days of intense, haphazard streetfighting – first to secure Tahrir, later to push on to the interior ministry in a long-held vendetta against the brutal engine of Mubarak’s rule which now falls under the military’s control. Back and forth it raged for hours at a time, as several hundred protesters armed with broken paving stones and Molotov cocktails charged down Mohammed Mahmoud Street to the security force ranks, scattering into the adjoining maze of lanes as the barrages of rubber bullets and acrid CS gas began.

As each night fell, the battles intensified. In scenes reminiscent of a post-apocalyptic sci-fi film, hundreds sporting gas masks and goggles threaded the debris-caked, pitch black streets, the air thick with petrol fumes, to the accompaniment of the steady whistles and percussive whumps of crowd control weapons.

Down by Falaki Street, protesters struck back with fireworks left over from Eid, the ranks of riot police visibly flinching as surreal flashes of green and gold lit up the frontline, before blasts of bird-shot clattered across the upper floors of the alley and sent protesters fleeing. Every few minutes brought fresh casualties: a keffiya-wrapped boy felled by a rubber bullet in the eye, a student-age girl in black hijab, pale face convulsing from the effects of a gas attack.

Stocky young men rode mopeds in tandem, slaloming to the frontline to scoop up the fallen then racing back through the parting crowd, the wounded slumped on the pillion between rider and amateur paramedic.

“They call us thugs anyway,” said one rider, his nose bridged with masking tape. He gestured to a student doctor: “You should keep away – Egypt needs educated, skilled people like you for the future. Let us die on the frontlines.”

Tahrir’s field hospitals were back in play too, as volunteer doctors battled to treat patients on the pavements and in houses of worship. Behind Tahrir Square, a Presbyterian church split emergency duties with the nearby mosque, laying out the injured on prayer rugs in the forecourt, its office overflowing with donated medicines.

Eva Boutrous, a 40-something church member, co-ordinated it all via a rigged-up PA system. “They’re ruining our country and killing our young – where’s this going to end?” she demanded.

As she spoke, 23-year-old Bilal was carted in, a live bullet lodged in his lower leg. While the clashes raged on, the two worlds – the carnival of the square and the chaos of the frontline – overlapped in a series of surreal cameos: an immense bag of pink candy floss bobbing above the crowd, framed against the smoke of burning barricades; a middle-aged man with a bucket on his head fleeing an onslaught then opening his broadsheet to read by moonlight.

By Thursday, as the military shored up their defences, talk once more turned to the elections which the army vowed would proceed as planned. Many on Tahrir talked of a boycott; others said they would vote but that the muted reactions of Egypt’s new politicians to events had rocked their credibility.

The Muslim Brotherhood’s stock has fallen the most. Although the group condemned the military-ordered crackdown, it has fallen short of calling for civilian rule or asking members to join the sit-in – participation that could be decisive.

With its political wing, the Freedom & Justice Party (FJP), expected to see the largest wins, the Brotherhood has a vested interest in stability. But such pragmatism sits badly with its previous supporters on Tahrir, many of whom cry betrayal and say they will switch votes.

“Salafists, leftists, Christians – they all have principles that let them take a stand against injustice.

“The Brotherhood promise but don’t deliver, they are out for themselves,” said 28-year-old Wael Yehia, his full beard and clean-shaven upper lip a marker of his sympathies.

He would vote for the Al-Nour party, which promotes ultra-conservative Islamist policies, he said.

His brother Mohammed echoed a common complaint on the square that America, with the $1.3 billion in annual military aid it gives to Egypt, was sustaining the status quo.

“There is American pressure on the SCAF [ruling Supreme Council of the Armed Forces] to hold steady because they’re scared democracy will bring the radicals,” said the 29-year-old lawyer. “They don’t care about what’s good for Egypt, only that we accept the American agenda like the army does.

“They think Islamists will come to power, rip up Camp David and go to war with Israel. I’m not for that, but we have to decide our own destiny.”

Another lawyer, 36-year-old Mohammed Assiuti, said he put his faith in the Tahrir protestors.

“All the parties are tarnished, all of them are playing for advantages. Maybe this movement here will bring new heroes,” he said. “But right now, who can honestly vote and think it counts?”

One self-declared revolutionary who said he wouldn’t let the bloodshed stop his vote was Mohamed Monissi, a general surgeon at a Tahrir field hospital.

To him, elections mean the death-knell for the Egyptian military’s strangehold on politics – something which has coincided precisely with the 60 years he has been alive.

“From Nasser to Mubarak it’s been one long dynasty. Tantawi wants that reign to go on,” he said, before turning his ire on the military’s economic interests, thought to control at least one-third of Egypt’s economy.

“They haven’t fought properly since 1973 – they are money-collectors, with no beliefs or thoughts. This is why we hate them and why we won’t accept their rule for even six more months.”

Once impressed by the FJP’s moderation, Mohamed said he was upset by the Brotherhood’s political games.

“The problem is, those who stand to win otherwise are the Mubarak guys with the businesses who’ve rebranded themselves. None of the other groups is ready to win,” he lamented.

At one point, the anti-military protests seemed to be gaining ground, with rumours of military defections and a series of piecemeal concessions from the military council.

Then on Thursday, it reappointed 79-year-old Kamal el-Ganzouri, prime minister between 1996-1999, to head a new cabinet, in a move greeted with ridicule by most on Tahrir.

Later on Friday, however, the US surprised everyone when Washington came out with its strongest statement yet on the unrest, calling on the generals to immediately cede power to Ganzouri’s civilian government once it convened in the next few days.