Refugees don't make wars. It's the other way around. The war in Syria has cost 250,000 lives to date. People run from killing.

The single best snapshot of how hideous the war is in Syria came from a man called Mohammed who had squeezed into a jerry-built rubber boat to cross the four miles separating Turkey from the Greek island of Kos with his wife, three-year-old daughter and baby boy. Mohammed told me for our Panorama documentary The Long Road that he had fled from Raqqa, now the citadel of the so-called Islamic State, IS – also known as ISIS or ISIL or, by its initials in Arabic, Daesh. "Raqqa is all blood and decapitated heads hung up on roundabouts. My three-year-old daughter saw the heads hung up with her own eyes. They would publicly execute in front of everyone. We were out and passed by Al-Na'em roundabout when we saw around 55 heads spiked onto metal poles."

British Prime Minister David Cameron has called IS 'a death cult' – and that description seems on the money.

The family were also bombed in Raqqa by Bashar al-Assad's forces – the Syrian ruler whose family have held sway over the country for 45 years. Mohammed told us: "My wife would cover the baby's ears, while I covered our daughter's ears, and we would hold them tight so they wouldn't hear the sounds. One day, a missile landed on the ground close to us. Since then, whenever my daughter hears bombing she goes mad."

I don't agree that we should tar everybody with the same brush. These people who are desperate for our help still need our help. The people who attacked us, they're the people who these refugees are fleeing

The war started after a popular rebellion against Assad's rule in 2011 – part of the Arab Spring – was put down by force. This triggered a military reaction by the regime's enemies. The difficulty for the Assad regime is that the president and the ruling clan are Alawites, a minority sect within the smaller of the two great branches of Islam, Shia and Sunni. In Syria, the Sunni population is the majority, the Alawites very much the minority. Critics of the US and British invasion of neighbouring Iraq in 2003 say that action destabilized the whole of the Middle East and the Arab Spring pushed Syria – as a repressed but essentially stable society – off the cliff.

The Assad regime is accused of killing civilians without compunction, especially by barrel bombs, crude terror weapons thrown out of helicopters, and using chemical weapons – again, against civilians. The regime is also accused by its detractors of freeing Islamist or jihadist fighters who joined IS. The regime denies all of the above and says that it is fighting terrorism.

On the long road from Damascus, you meet people: some of whom are fleeing IS, some fleeing the Assad regime, and some fleeing the other groups of Islamist gunmen thrown up by the war. Many of the people fled the war in Syria early on, but found life in refugee camps in Turkey, Lebanon and Jordan increasingly difficult: it's hard to earn money. Many refugees complained about the Turkish authorities' decision not to teach their children.

But in August this year, the German Chancellor, Angela Merkel, announced that Germany would accept refugees if they got to its land borders: perhaps 800,000, perhaps a million. This was a pull factor. The result was – is – perhaps the greatest movement of people in Europe since the second world war.

Road weary

Along the road, it's the ordinary, extraordinary people you meet who stick in the mind. Somewhere where Macedonia stops and Serbia starts, an old man with a stick trudged along a railway line. In a beautiful 1940s English accent, he greeted me with a "Good evening" and asked the way. I didn't have much of a clue where we were but it was his civility, his forbearance that struck me.

No question, there were other people on the road, too: economic migrants. I met one Syrian 'refugee', an aircraft engineer, who told me that he'd left his country for Dubai in 2002. He didn't strike me as much of a refugee.

My own observation was that the authorities and the border police, by and large, in Greece, Macedonia, Serbia and Croatia didn't really want the refugees but weren't going to prevent them from getting to Germany and beyond. In Hungary, it felt different, the refugees treated as criminals, held behind barbed wire in metal cages.

We met a family from Kobane, a Syrian Kurd town that became a battlefield between Kurdish freedom fighters and IS. Mustapha and his family had been given wristbands with barcodes by the Hungarian authorities. The barcode didn't look as though it could tell the difference between an IS warrior and a normal human, but it made all humans look like cereal packets.

With Mustapha was his auntie, Fakria, who cried while she tried to explain her misery. She'd been detained in hospital in Hungary and her son had to continue on – and as a result she spent two grim days at Budapest railway station on her own, going up to complete strangers with her only word of English: "family, family". Eventually she bumped into Mustapha, a distant cousin but one from the same town. In the September heat, the Hungarian authorities made everyone walk the last couple of miles to Austria. Mustapha had a club foot. He made it, but Fakria collapsed at the Hungarian border post. I thought she was dying in front of my eyes – and then the Hungarian Red Cross people wiped some dextrose on her lips and she came round. She was a diabetic.

One of the most moving moments of my life was watching Fakria struggle across the Austrian border – and into an ambulance. I put up a post on a BBC Facebook page, showing Fakria's call to be reunited with her son, and it got almost 400,000 hits. A clip of Fakria reunited with her son at Vienna station got almost a million views.

Another story of a family split up concerned Azam, a six-year-old from Damascus. We met him first in Serbia. He had a broken jaw and was last seen by us getting into an ambulance with a man who told us he was his father, but we suspected was his uncle. But the man and Azam vanished from hospital. Social media created a hashtag #FindAzam and, for BBC Newsnight, we did just that – with the help of BBC Arabic. Azam ended up in Hamburg and his parents have now reached Germany, too. Azam's story was one point of light in an otherwise bleak autumn.

The road from hell

Survival instinct

Michael O'Connor from South Shields and Sara Badel from Lyons are two lovers who played dead amidst the dead at the Bataclan music venue in Paris in November. I interviewed them for our BBC Panorama film on the massacre. Michael is bearded, a hipster, thoughtful and reflective; Sara is funny, passionate, uncommonly beautiful. She wanted to go to the band that night, she was the fan who wanted to stand right by the stage; for him, it was his first ever night in Paris. Together, what started out as a great night out ended up a hell on earth.

After the gunmen opened up, everyone ran for the exits. In the crush, the dead bodies piled up and amidst them, they hid. After the initial rapid fire, the gunmen hunted the living, anyone who moved, who showed signs of life. The trick to survival was to lie still, to make no sound. Michael told me: "The really eerie thing was that the amp from the gig was still on in the background, this fuzzy sound, the lights were really dim and there was a chorus of mobile phones, 50, 60 people's mobile phones, all ringing, ringing all the time and it made it feel so unreal. It must have been people ringing over, over and over again to try and get in touch with their loved ones."

When Sara's phone rang, she ignored it and stayed frozen. Her survival technique was to concentrate fiercely on the idea that they both would survive. She was lying in a horribly awkward position, her neck cricked, her hair and back covered in someone else's blood: "I knew I would make it alive, I knew it, I can't explain it and it's completely irrational now that I'm looking at the figures, I could have been injured, I could have been anything but Michael was saying lovely things to me."
"I was saying my goodbyes to be honest," interjected Michael.

The war in Syria has cost 250,000 lives. refugees are running from the killing

They made it. After two-and-a-half hours of playing statues, the French police took back the Bataclan and they stood up. They hoped that many others playing dead would stand up too – but they were really dead. At the music venue, in all, 89 people were killed.
In our long interview I mentioned that I had met a refugee from Syria, Sobhe, who told me on the Greek island of Kos in early September that he was afraid of the so-called Islamic State or IS hiding amongst the refugees: "I'm afraid these ISIS men, these terrorists, they will destroy the image of other people, of hundreds of thousands of people."

Michael saw Panorama: The Long Road on BBC World News. "I don't agree that we should tar everybody with the same brush. These people who are desperate for our help still need our help. The people who attacked us, they're the people who these refugees are fleeing."
Sara agreed: "They're the people that can understand the most what we've been through."

How and where we fight IS and what we do with the people who seek sanctuary from the war in Syria are big decisions. But Michael and Sara's humanity, their consideration for others even while still suffering from shock, was something I shall never forget. Our open society must be properly defended and kept secure.

Against the power of love, killers have no chance.

Watch John Sweeney in Panorama's 'The Long Road' on BBC iPlayer here.

Get involved