Migrants in Calais are becoming “more violent and aggressive” in their attempts to cross the channel to England, a French policeman has told The Local. As many as 1,500 migrants, mostly from Eritrea, are camping out near the French port looking for opportunities to make the crossing.

In the last few weeks, the migrants have been growing increasingly assertive in their efforts to storm the port, with police having to resort to using tear gas to hold them off. “The other day, two to three hundred migrants tried to get into a lorry park and we fired tear gas to scatter them because there are too few of us to control situations like this any other way,” Gilles Debove, the Calais area delegate for the French police union told the Telegraph.

Another policeman, speaking on the condition of anonymity said: “They are becoming more violent and aggressive and we have to use tear gas more and more.”

Debove added: “We’re also facing an increase in crimes by migrants who mug people, steal mobile phones and carry out sexual assaults,” but said that legal proceedings against the migrants often collapsed because of translation problems. Under French law, suspects must be able to understand the charges brought against them so that they can defend themselves.

“When we arrest them, they speak English, but once they’re charged, they refuse to speak anything but their own language and there’s a shortage of interpreters, so we’re often forced to release them,” Debove said.

Local mayor Natacha Bouchart told the media that the migrants want to get to Britain because they see it as an “Eldorado”. Under EU laws on free movement of people, asylum seekers are meant to stay within the first EU country they arrive at to have their application process. But in practice, most of the migrants use the fact that continental Europe is borderless to travel freely to the country of their choice. For many, that country is Britain.

“Why are we prevented from going to Britain after coming all the way up here?” asked Nasir, a Sudanese national who recently took part in a demonstration again the local police crackdown.

It is difficult to deport the migrants back to their African and Middle Eastern home nations thanks to the poor human rights records of those countries. Many of the migrants are from Eritrea, which is currently under investigation by the EU for human rights abuses including extra-judicial executions, torture, and forced military conscription lasting decades.

The plight of the migrants has led some campaigners to call for France to offer them asylum. But the migrants themselves are not interested in applying on French soil. A local official, who also wanted to remain anonymous, said that some do apply for asylum in France “so they face less trouble from the authorities here while their applications are considered, but it doesn’t stop them continuing to try to get to England.”

He told of migrants who had been driven to reception centres at the other end of France to have their applications processed, only to “walk out the next morning and make their way back to Calais”.

Bouchart last week called on the British government to help fund a solution to the problem, after 150 migrants broke into Calais port and attempted to board a British-bound ferry. They were held off by ferry staff who turned fire hoses on the men and pulled up the ramp before they could board. The British government responded by donating the high security fencing used at the recent Nato summit in Cardiff, Wales. Bouchart has threatened to close the port if the situation doesn’t improve.

Security measures have also been put in place around lorry parks in an effort to deter migrants from stowing away on lorries bound for Britain. Drivers face punitive fines of up to €20,000 ($25,000) if stowaways are found on board their vehicles.

One Slovenian driver, Frank Ravnjak, has been stuck in Calais for over a week after British customs officials found 16 stowaways on board his lorry loaded with tortellini. “I don’t know when I will be able to return home,” said Ravnjak, who was fined and had his lorry confiscated and its cargo destroyed. Another Greek driver told reporters that he had recently found 3 men hiding on the axle of his truck.

“The moment the trucks stop, the migrants scramble aboard, even in broad daylight,” said Arnaud Dequidt, a director at transport company Carpentier. However, the manager of one lorry park, Olivier Carre, said that the police response was not good enough.

“Last week, a lorry entered with seven illegal immigrants. We called the police and they made them walk to the roundabout at the end of the road and went off,” he sighed.

Immigration minister James Brokenshire, commenting on the situation in Calais, said Britain is “no soft touch when it comes to illegal immigration”.