It has become a common sight for the people of Calais - men chasing lorries, pulling open the rear doors, and clambering inside, sometimes hanging precariously off the back, as the lorries swerve to shake off their unwanted cargo.
Clive Myrie explores a makeshift camp for illegal migrants
They are the migrants, who emerge each afternoon from makeshift camps to sit near busy road junctions and try their luck as trucks come by heading for the French port, and Britain.
That it happens in broad daylight as well as the dead of night is a sign of how brazen, and how desperate, these people have become.
But watching it happen can be risky too. We were chased off by men carrying big bits of wood as we tried to film. They were the traffickers who trade in the misery of many of their fellow countrymen.
"To get to Britain from here we people pay £500 ($700), or £700, and even £1,200 just to cross this line," says Zabir, a migrant from Afghanistan.
It is just the latest in a long line of payments to get to this far. Most have already spent thousands getting from their home countries to the point in northern France closest to Britain.
"People are compelled to do it," Zabir continues. "If someone tells me they will get me into the UK, I will pay him anything."
'I am an animal'
Zabir and his fellow Afghans live in a shanty town growing rapidly out of some scrubby woodland near the lorry parks where truckers from across Europe stop to fill up with fuel and rest before continuing to the UK.
Ad hoc international and ethnic boundaries have sprung up across the town of Calais. Afghans live in a desolate place known as "the Jungle", Iraqis have their own encampment not far away. East Africans live in a terrace of derelict buildings in the town centre.
The Jungle is a filthy, squalid camp with shacks made from old bits of wood, corrugated iron, plastic sheeting and blankets.
Sabella's mother wants her to go to school in England
There is no water, no electricity and no sanitation.
It is starting to look permanent though. This week the men there began work on building a lashed-together mosque.
Ethnic disputes break out frequently. One man was recently murdered here by someone from another tribe. His friends have built him a memorial made from old breeze blocks.
Zabir, an educated and articulate man, is deeply depressed. "Is this humanity? Is this civilisation?" he asks.
"We have a very bad life here my friend, very bad. For myself I do not think I am human any more. Here I am an animal."
It is estimated that there are about a thousand migrants in Calais, and at the moment they get no help from the French authorities.
Charities have stepped in to fill the gap. Every day hundreds of people turn up for the twice-daily handouts of food. Once a week they can collect donated clothes.
The authorities have been in a quandary about what to do for some time now.
In 2002 - under pressure from Britain - the refugee centre at nearby Sangatte was closed and publicly bulldozed.
Sangatte had been seen as an official encouragement to migrants to come and have a go at getting into Britain illegally.
More recently, migrants have been treated harshly. The hard-line French riot police, the CRS, have been making life difficult for them.
Migrants complain that they have had tear gas thrown into their camps, and are frequently arrested and harassed.
But they are not sent back home.
Now, there is a sign that the authorities acknowledge that the get-tough approach is not working.
French Immigration Minister Eric Besson told an interviewer this week that the government would build a series of temporary reception centres in Calais where migrants could get food, sanitation and information about their rights.
Such a move would cause great concern in Britain, where some fear that a series of "mini Sangattes" could simply send out the signals all over again that the welcome mat is being rolled out.
But no matter how badly they are treated, the migrants continue to come.
At the derelict houses occupied by people from east Africa - in particular countries like Somalia, Sudan and Ethiopia - I met Ibrahim from Eritrea.
He said he paid $7,000 to get here in a perilous journey from home, across the Mediterranean in a rickety boat, and on to France.
He is trying to reach his three children, who have been in Britain for the past four years.
"Everybody here has his aim, his dream," he said.
"For me it is to get to my children to enjoy life with them. That's what I am fighting for. I need my family. I need my wife and my children. It has not been an easy four years."
Ibrahim says he has tried 20 times to hide himself inside lorries heading to Britain, but each time his mission has failed.
"Will you keep trying?" I asked him. "Even a hundred times," he said. "I have to get there. I have to reach my goal."
In the derelict house I was surprised and concerned to see children living in such dark, damp and dirty surroundings.
One girl, five-year-old Sabella, was living in a room with her mother and perhaps 10 other men to each room.
They had also made the long and dangerous journey from Eritrea.
Isn't it dangerous for her, I asked her mother?
"Of course," she shrugged, "but what else can I do? I want to go to England not for me, but for my baby. There are good schools there. I want her to learn English."
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