French workers on Monday began bulldozing half of the "Jungle" refugee camp in the northern port city of Calais that is used by thousands of refugees hoping to reach Britain for a better life.
20 workers began destroying makeshift structures under heavy police protection after the French government won a legal battle against activists that allows it to dismantle part of the camp.
Regional Prefect Fabienne Buccio said the police presence was necessary as "extremists" could try to influence refugees into turning down housing offers or buses to reception centres.
Although the situation was mostly calm one member of the British "No Borders" activist group was arrested for trying to prevent the clearing of the site.
"We are carrying out our orders so that the migrants leave the camp and we will continue this work this morning,” said local authority head Fabienne Buccio and accused No Borders activists of threatening workers.
Buccio said three-quarters of the shacks in the southern half of the camp were now empty after refugees were encouraged to leave in recent days.
Local authorities, who have promised that no one will be forced out say that between 800 and 1,000 out of the 3,700 people live in the camp will be affected by the eviction.
But according to a recent census carried out by charities there are at least 3,450 people in the southern part alone, including 300 unaccompanied children.
The refugees have been offered heated accommodation in refitted containers set up next to a nearby camp, but many are unwilling to move there because they lack communal spaces and movement is restricted.
They have also been offered places in some 100 reception centres around France.
The camp in Calais, which has ferries across the English Channel and the Eurotunnel rail to Britain, has existed for years.
But thousands of refugees fleeing war and poverty have converged on the northern port over the past year, which has become a flashpoint for Europe's refugee crisis, fueling far-right sentiment on both sides of the Channel.
Most attempt to climb illegally onto trains using the Channel Tunnel or lorries heading to Britain which they are drawn to by family or community ties, because of a shared language, or because they think they have a greater chance of finding work there.