CALAIS - French authorities said on Wednesday they had finished clearing the "Jungle", a squalid shantytown outside Calais built by migrants who had hoped to make the passage to Britain but whose last inhabitants are now mostly dispersed around France.

The operation passed off peacefully for the most part, though some migrants torched tents and shelters in a last act of defiance as their hopes of a new life in Britain evaporated. "This is the end of the 'Jungle'," Calais regional prefect Fabienne Buccio said. "Mission accomplished."

The prefecture said it had brought 4,404 adults and their children in from the cold and damp of the Jungle for resettlement in 450 centres around France since the start of the week.

A further 1,200 unaccompanied minors had to be housed temporarily near the Calais site, their futures unclear much to the dismay of human rights groups.

Earlier in the day, riot police spread out around the camp, and fire trucks moved in to put out blazes that sent plumes of smoke into the sky.

Migrants fleeing poverty and war in the Middle East, Asia and Africa congregated to Calais hoping to cross the short stretch of sea to Britain by leaping on trucks and trains, or even walking through the tunnel under the Channel.

Britain refused to accept the vast majority of them - apart from a number of unaccompanied child migrants now being processed separately - and high fences were built to keep them away from the port traffic, but still they came.

Local opposition to the sprawling slum, along with growing criticism from right-wing politicians, finally stung the French government into action.

The Jungle has been an emotive subject in both Britain and France, whose populations share concerns about the pace and scale of immigration.

The British referendum vote this year to quit the European Union was in large part driven by such worries, and stoked by scenes of the Calais migrants trying to force their way in.

And now that Britain is leaving the EU, right-wing French politicians with an eye on winning power in next year's elections say they want to tear up the agreement under which Britain's border controls are conducted in France.

This would remove the problem from Calais and allowing migrants in future to reach Britain unimpeded.

Still, there is no guarantee the camp clearance will end attempts to reach Britain, a country that many arriving in Europe see as their brightest hope of making a new life due to its plentiful jobs and English language.

The numbers of migrants reaching Europe are sharply down on the 1.3 million who arrived in 2015. But the inflow is still substantial, with more than 300,000 making the hazardous Mediterranean crossing in 2016 so far, and many of those likely to favour Britain as a destination.

Hamid, 30, from Afghanistan, said he had been among those setting fire to shelters in the Jungle, and still hoped to cross the Channel to Britain.

"We don't care about problems that are to come after this. We did it because we don't want to stay in France," he said. "We want to go to England and England only. It doesn't matter if I go to jail here."

France has repeatedly urged Britain to take in all the unaccompanied minors at the camp, while Britain has said it expects to accept about half of them.

The Calais region's prefecture said in a statement that over 200 had already arrived in Britain.