Special report: 'I have no heartleft, How will this end?'

He sat in near-darkness and total silence: a young man, with a hard face and a reputation to live up to.

In a city paralysed by fear, he is among the most feared. He is a Syrian army sniper, and I had come to meet him.

The soldier who had taken me up the staircase and into the gloom of the house on the front line in Homs would not give the sniper's name for fear that his family would be killed by rebels bent on revenge.

The sniper's nest was almost airless. He said nothing while I was there. He was watching and waiting for his target to appear.

Through a crack in the wall of his top-floor firing point, his rifle and telescopic sight were aimed at the balcony of a house already pockmarked with bullet and shell holes.

He had seen a rebel gunman appear there and quickly pull back an hour earlier. He scarcely registered my presence, so intent was he on the kill. I felt nearly queasy watching him, hoping his intended victim would stay hidden.

I left before he fired, but the crack of single shots outside was proof that on the front line of one of the deadliest cities in Syria, this is still a war of snipers - men with the blood of thousands on their hands, the most feared gunmen in a long and deadlocked war.

I was out into the blinding light and across a back street, past piles of stinking rubbish, with three Syrian soldiers ahead, gesturing at me to sprint across the next junction. Head down, I raced for my life to avoid the single shot from the other side. Both regime and rebels use the sniper to lethal effect.

Up again into the darkness of another house, this time to see two snipers, back to back, their gun muzzles inched through holes in the walls.

Their war is fought across short distances. One of them said his target was a rebel position just 50 yards away. Behind him, the young man with the blackened face was aiming for 200 yards.

Theirs is also a war of fixed positions. Since May, the front line in this district of Homs, Bab al-Sebaa, or Lion's Door, has moved just 500 yards - 100 yards a month - at the cost of hundreds of lives. The day before, five Syrian soldiers were killed there.

Despite the devastating shelling of the nearby district of Baba Amr earlier this year and President Assad's appearance there to confirm its recapture, fierce gun battles are still being fought.

Syrian troops would not let me get closer. But I could hear everything from a distance - machine guns and AK47s were firing almost incessantly.

Twice this year, I have crossed the front line to talk to rebels in Homs. They were Syrian almost to a man. That's not how the regime's troops see their enemy.

"Most of them have long beards," one soldier told me. "They're jihadis and foreigners: Turks, Chechens, Saudis." Another said European Muslims were among the rebels. "British, Germans, French". The regime routinely refers to them as terrorists.

I was asked regularly why Britain was supporting terrorists backed by Saudi Arabia, who wanted to overthrow a secular regime.

It's almost a shock to see civilians in parts of Homs. They don't flinch when shells or shots ring out. I bumped into Saleh Shattour in the street. He wasn't an old man but he looked old, his face, like his mouth, collapsed in sadness. He said life was very hard now - he couldn't count the number of neighbours who had been killed. When I asked him how he felt in his heart to see his neighbourhood like this he struggled, then broke down. "I have no heart, no heart left. How will this end? God alone knows," he sighed.

The war in Homs is macabre. On one house, a half-sized plastic skeleton had been left hanging from a nail. At what I was told was the deadliest junction in the area - you could tell by the speed at which the soldiers sprint across it - a mannequin in a shocking pink dress had been positioned in the middle, as if to mock the rebel snipers on the other side.

But it was the next position on the front line that shocked me. It's one thing to hear about the widespread use of torture in this dirty war, especially by a regime bent on crushing the revolution by whatever means necessary. It's quite another to see the instruments of torture in front of you.

Through holes in walls and houses, I reached a building the Syrian troops said they'd taken from rebels two weeks earlier. What they claimed they had found there still lay scattered around. It wasn't the bags with Saudi Arabian marking that first caught the eye, it was the meat hooks.

A couple of the soldiers lifted up a makeshift wooden scaffold, took one of the meat hooks and attached it to the underside. They demonstrated how it would work. The prisoner would stand on a stool, be hooked onto the metal - I shuddered to think how - then the stool would be kicked away and he would be beaten as he was hanged.

There were bloodied knives lying around, and other implements that didn't bear thinking about. The soldiers claimed this was a rebel torture centre, but they seemed to know how everything worked. At the far end of the building was a deep well into which, the men said, the bodies of the dead were tossed.

Neither side appears to be winning in Homs, the focus of long and bloody fighting. The governor of the city, Ahmad Moneir Mohammad, said he was confident the war would all be over in a month. I suggested that after 18 months of stalemate, that was optimistic. He wasn't having it. "Eighty per cent of Syria's problems will be solved when Homs is retaken," he said.

But the explosions that detonated for an hour outside his office gave the lie to any idea that this war is winding down.

It is not abating in Damascus, the capital, either. Each time I return there, the conflict has bitten deeper. This time, plumes of black smoke rose from the southern suburbs, forming a huge arch over a city that echoed to explosions from the army's bombardment of rebel-held areas.

Once, residents of Damascus believed the fighting would never come their way. Now, there is no one here who cannot see and hear the shelling all around them.

Clusters of tanks sit on main roads. Checkpoints everywhere grind the traffic to a halt. It's a gridlocked city trapped in a deadlocked war.

But two months ago the rebels thought they were on a roll. They had just killed the defence and interior ministers, as well as President Assad's brother-in-law, in a daring bomb attack on a high-security building in Damascus. They followed it with a ground assault on both Damascus and Aleppo. Rebels in Aleppo attacked from three sides and took huge swaths of the city, much to their surprise, within two days.

In the capital they quickly dominated half a dozen suburbs: poor, Sunni districts where the revolutionary spirit burns and the regime is loathed. Syria's army was suddenly on the back foot, the regime reeling.

But with the help of hundreds of artillery pieces, mortars and warplanes, President Assad's men have regained the initiative. Suburbs have been effectively sealed, the perimeter saturated with troops. Checkpoints made movement in or out almost impossible.

The destruction I have seen is extraordinary. Houses bulldozed, blocks of flats collapsed, the splatters of shells marking every building and road. Neighbourhoods have been destroyed.

In the past few days, the army and its brutal militias have been, in the words of the state media, "cleansing the areas of terrorists". No one knows exactly what this entails, but reports from activists and human-rights groups suggest that dozens of men, and in many cases women and children, are being murdered in a drive to inflict collective punishment on any district that has dared to welcome revolutionaries.

The tactic is working.

Rebels withdrew from the suburbs around Hajar Al- Aswad, conceding that they had run out of ammunition and local support. Clearly, many sympathisers who would dearly love to get rid of President Assad also fear the terrible revenge of the regime for harbouring rebels.

A few days ago, President Assad appeared on television with Iran's foreign minister, smiling broadly, perhaps content that his men have recaptured much of his capital.

He was probably not smiling just before 7am on Wednesday when an explosion rattled the windows of homes half a mile away, around the presidential palace. Six or seven minutes later there was another huge blast. The rebels were striking back. They had bombed the headquarters of the army, supposedly one of the regime's most secure buildings.

The method as well as the target was significant. The first bomb was detonated by the side entrance by a suicide bomber in a white van; the second exploded inside the building, and then at least half a dozen heavily armed gunmen began an attack that lasted for more than three hours. The regime says only four guards were killed. The rebels claim dozens died - although they often inflate the death tolls of their attacks. But the tactics were straight from Iraq, straight from the manual of al-Qaeda.

Syria's Arab Spring revolution is now entering its second winter. It is a very long way from the flag-waving, pro-democracy protests of its birth. It is a fully fledged war, one that has claimed - by one estimate - more than 30,000 lives. August was the deadliest month so far, with the London -based group Syrian Observatory for Human Rights putting the death toll at 5,400. That's 180 a day. Last week, the toll exceeded that nearly every day. The sudden spike in casualties has been blamed on the regime's fightback in Aleppo and Damascus, especially its use of MiG warplanes.

The Assad regime has been accused by Amnesty International and foreign governments of using the planes to bomb residential areas indiscriminately. Pictures from Syrian state television illustrate an Aleppo more like Berlin at the end of the Second World War than the business capital and sophisticated city of six months ago. Reports from the rebel side suggest they are hopelessly outgunned, starved of ammunition and incapable of holding the ground they took with such optimism eight weeks ago.

After the bombing of the army headquarters in Damascus my cameraman colleague, Tony Hemmings, producer Paul Tyson and I had a taste of what many Syrians face.

The nerves of the soldiers were clearly frayed but our presence at the scene tipped many of them over into rage. We were surrounded by a mob of soldiers, secret police, intelligence officials and militiamen in civilian clothing. They wanted to take our camera and the footage we had shot. They did not want the humiliation of their charred and smoking command centre shown to the world.

Brilliant, quick thinking by my cameraman saw him extract the memory card from the camera and hide it in his underpants.

Secret policemen saw his move, searched his trouser pockets but failed to find the card. We were roughed up, marched off, hands pinned behind us, and the camera smashed to pieces as we were taken away. The mob shouted that we were British. A handgun was waved.

It was an uncomfortable few minutes. But our ordeal ended when more senior army officers intervened and saw the official visas in our passports.

Tens of thousands of Syrians have not been so lucky. They have been taken away and never seen again. Their families have no idea whether they are dead or in one of Syria's hundreds of detention centres.

The war grinds on relentlessly, chewing up its young, stoking sectarian hatreds, multiplying atrocities week by week, spiralling into ever more horrific mayhem.

In Homs, the young, hard-faced men sit silently on the top floors of shattered buildings and wait, their fingers lightly on the triggers; time on their hands, death on their minds, victory in their sights.

Theirs is a war of single shots. But it has gone far beyond that now. Up into the cockpits of Russian-made fighter jets, where pilots try to crush the revolution from 10,000ft. Down to the bowels of feared intelligence buildings where tens of thousands of prisoners are beaten and tortured with metal bars like those I saw in Homs. Into the stony ground of Syria, where 30,000 dead now lie. And, finally, to the very doorstep of President Bashar Al-Assad who once declared his country immune from the revolution; a man who must sit now and wonder, as his windows rattle, where his future lies.