Unaccompanied Syrian children as young as 10 are living under tarpaulins in rain-sodden ditches far out in the countryside near Calais, France.

I met these children recently when I went to see how the charity I work for, Doctors of the World, helps the 2,000 or so migrants trapped in the Calais purgatory.

While most people know of the infamous ‘Jungle’ where the majority of migrants live near the port, few are aware of the other 20 or so settlements dotted around the region.

The first of these I saw was a squat in an old recycling yard. As we approached, big yellow letters loomed above us, rearranged to read ‘WE WANT FREEDOM.’

Inside, the scene was apocalyptic. Among the rubbish, debris and heavily graffitied walls were scattered tents and groups of men, mostly from Darfur, some from Syria and Afghanistan, huddled around fires playing cards, the smell of wood smoke clinging to everything.

Hussein, from Darfur, spent eight days at sea traveling from Libya to Italy, and was without food and water for three of those days.

‘I will be killed if I try to go back,’ he said. ‘David Cameron says “England is the best” and I believe him. So that’s where I’m going!’

Behind a nearby supermarket another group of 100 or so migrants live in a field. It had been raining for three days and the ground was like a Glastonbury mud bath. The camp had no running water or toilets and I was told that the migrants were barred from the supermarket.

Despite wearing only flip-flops and woefully inadequate summer jackets, the residents greeted us with smiles and handshakes.

‘London is the best city in the world!’ said Samir, an electrician from Darfur, after he heard where we were from. He had spent two weeks crossing the Sahara Desert with little food as part of his journey.

 I asked what it is like living here.

‘It is so terrible here,’ he said matter-of-factly, still smiling.

We had to drive far out into the countryside to a place near St Omer to visit the last, and most shocking, settlement, where a group of 20-30 Syrians were living in a ditch.

As we squelched down the remote muddy lane in the rain, it was hard to believe anyone could be living there. To our left were tilled fields, now just mud, and to our right were bushes leading down into a long ditch. I had turned up my trousers to the knees to avoid getting muddied and I thought I looked silly.

When we got closer a group of boys appeared from the bushes, with an adult. Recognizing our charity logo, they huddled beneath our umbrella. Only the adult spoke – he was from Aleppo, as were all the boys, who stood with bare feet on the tops of their wet and mud-caked shoes. I stopped thinking about my trousers.

The boys were aged between 10 and 15 and were muddied and unwashed, all there without their families. The 10-year-old was scratching because of scabies.

They took me down into the ditch beneath the tarpaulins to a small fire. They camped in this far-flung location because there was a service station nearby where they could try to board trucks.

‘There is so much we don’t have here,’ the adult told me. ‘But it is better than Aleppo.’

He added: ‘But we will not be here long’.

My French colleague later told me this was a common delusion, perhaps a necessary one, and that it usually took many months to cross the Channel.

So how could children be living for long periods of time in muddy ditches in a rich, supposedly civilized country such as France?

Part of the reason is that many of the refugees are distrustful of authorities, largely due to their experience with the French police, who are often the first point of referral for unaccompanied minors.

We hear regular reports of police brutality and harassment, such as arresting migrants, including women, and driving them long distances before dumping them by the motorway, forcing them to walk back. Police regularly destroy migrants’ property, including their phones, which are often the only connection people have to their families. They also beat them up.

‘They come early in the morning and chase us through the fields,’ says the adult. ‘When we come back all our things are broken’.

Walking back up the sodden path, I felt wet and cold, already sick of the mud and I could not wait to change my shoes and get in the car. I looked round at the boys standing in the drizzle; the youngest one was waving and it felt wrong to be leaving them there.

Back in my warm hotel room, I watched the rain through the window, knowing they were still out there, only a few kilometres away. The news that night featured reports from Syria and Sierra Leone, but nothing about the very real crisis happening here in Europe, just a short truck drive away from England.

Doctors of the World (Medecins du Monde) provides medicine and hygiene kits to migrants in Calais as well as building toilets and washing facilities.