The insults and the pushing started as hunger pangs drove a crowd of several hundred migrants towards a charity van carrying the cheese sandwiches and bananas that are their daily meal.

A young Afghan man ran through the mud to the front of the queue, but was shoved aside by a tall Iranian in a black coat and a grey, woolly hat. For a few seconds, the two men stared in fury at each other across the bleak, industrial land in northern France that has become their base while they seek the chance to reach Britain.

Then the tensions born of desperation exploded into violence. The Afghan found a stick, which he swung wildly above his head at any Iranian within reach. One responded by trying to slash Afghans with a length of broken wood. Another hit out with a brick.

Punches flew. Charity workers screamed for calm. Eritreans scattered out of the way of the battle, which ended when the Iranians turned and walked off, muttering what were almost certainly oaths of vengeance. “It's so stupid,” said Zabihullah, a 17-year-old Afghan. “But this is what happens when people are forced to live like animals.”

Welcome to Calais — six years after Nicolas Sarkozy, then Interior Minister, announced an end to the migration crisis that was straining Anglo-French relations when he closed the refugee centre in Sangatte, a few miles along the coast. The problem would go away, he claimed. It has not.

“Nothing much has changed except that now these people have to live outside in the cold and the wet,” said Monique Delannoy, who runs La Belle Étoile, a Calais-based charity. “They are still coming here and they are still trying to get across the Channel.”

The recession, rising unemployment and wildcat strikes against foreign workers had done nothing to alter their view of Britain as a haven of peace and prosperity, she said. “When you've been told that you have to go to England, when you've travelled for months and when you're only 35km away, the last thing you're worried about is the economic situation there.”

There are about 500 migrants in Calais — Afghans, Pakistanis, Iranians, Iraqis, Sudanese, Somalis, Ethiopians, Eritreans, Bangladeshis and others. Almost all are men, sent by their families to earn money in Britain, some travelling with boys as young as 10. They squat in disused buildings, sleep in makeshift tents in woods that have come to be known as the Jungle, and huddle around campfires as temperatures drop below freezing. Almost all have paid criminal gangs $5,000 to $20,000 to bring them from Jalalabad, Mogadishu or Tehran to Calais, where they risk their lives hiding under lorries or trains crossing the Channel.

Most are arrested by the French police regularly — about once a week, on average, they say — only to be released a day or so later to try their luck again. Some - between four and ten a night, according to local officials and the migrants themselves — make it to Kent. None will countenance staying in continental Europe, still less returning to their country of origin. “Britain will accept me,” said Zabihullah, from a wealthy family in Laghman province, eastern Afghanistan. “I will finish my studies there and then I will find work.”

Next week Eric Besson, the French Immigration Minister, will ask Phil Woolas, his British counterpart, for help with what is becoming an explosive issue in France amid exasperation over the failure to curtail migration to the West. He is likely to seek money, technology and more British Border Agency staff in Calais in an attempt to fulfil his pledge to make the port secure. Mr Besson told La Voix du Nord, the regional newspaper: “The British must involve themselves more actively in strengthening controls and security in Calais.” The minister also promised visas for migrants who denounce the people-trafficking gangs — one of which was discovered recently by French police to have earned €15 million in a year from the trade.

Charities doubt his ability to do better than any other immigration minister in France or elsewhere, in the face of a stream that has its source in Third World poverty and danger. Take, for instance, Javed, a 23-year-old Afghan squatting by a fire as he waited for La Belle Étoile's food van. He said, in impeccable English, that he had worked as a translator for the Royal Navy's Special Boat Service before joining the Afghan special force that has the job of curbing opium production. Last year he received a letter from the Taleban to say that they knew about his activities. “They said they would damage my family. My father obliged me to leave the army and Afghanistan.”

Javed's father and uncle borrowed $14,000 to pay smugglers to take him by car, lorry and boat and on foot on a seven-month journey through Iran, Iraq, Turkey, Greece and Italy to France. He has been in Calais for three months, sleeping under a plastic sheet in the Jungle, trying every night to slip under a lorry bound for Britain. “I've been arrested 12 times,” he said. “The police always take me out of Calais and leave me. I have to walk back - it takes two hours, three hours, five hours sometimes in the middle of the night. But I'm not going to give up.”

Squatting next to him was Imran, his face cut, swollen and bandaged after he had fallen trying to jump under a Eurostar train. “Look at him, look at how we have to live,” said Zabihullah. “I know the UK did not invite us and I know we are illegal. But you can't leave us here like this.”

A few metres away was a group of young Eritrean men who have found shelter in abandoned council houses that are due for demolition because of a high asbestos content. Among them was a 12-year-old boy shivering in the cold. Abraham, 22, from Asmara, had spent $6,700 to travel through Africa to Europe and was prepared to spend a further $1,000 for a people-smuggler to take him in a car boot or lorry to Britain. “We've got to get out of Calais,” he said.

With French charities determined to highlight the migrants' plight and politicians in Calais calling for them to be removed from the town, Mr Besson is under pressure to authorise a new refugee camp. He has refused to do so, but has agreed to the installation of showers and a portable building from which charities can serve meals.

Zabihullah says that it is the least he can do. “We were all sold the idea of European civilisation,” he said. “We have got to Europe, but we are looking for the civilisation.”

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