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By Matthias Blamont

CALAIS, France, Oct 26 (Reuters) - Migrants at the "Jungle" camp in Calais queued to be relocated on Wednesday as authorities cleared the shantytown still smouldering from blazes and gas-bottle explosions overnight after departing residents set fire to shelters.

Local opposition to the squalid and unsanitary camp which at one point housed more than 6,000 people, along with criticism from right-wing politicians, has stung the French government into launching a clearing operation which began on Monday.

More than 4,000 migrants, who had come to Calais hoping to cross the short stretch of sea to Britain by trying to leap on trucks and trains or walk through the tunnel, have been bussed out of the camp and relocated around France. "The operation will continue today to remove the empty shelters and to avoid them being set fire to again," a local government spokesman told France Info radio as dawn broke to reveal the smouldering remains of what had once been one of the camp's main thoroughfares.

The Calais prefecture official said one person had been slightly injured in his inner ear by one of the explosions and had been taken to hospital.

Late on Tuesday, regional prefect Fabienne Buccio said it was difficult to prevent the fires, which became something of a ritual earlier this year when one section of the camp was partly dismantled.

"Some migrants follow traditions - we asked them not to do it - but they set ablaze their tents and their shelters when they leave," she said.

"We told them not to do it, but some...do it anyway. We are on standby, the fire brigade is in the vicinity to guarantee security and to prevent the fire from spreading."

People fleeing poverty and war outside Europe have over the past few years congregated at Calais, the main port of entry to Britain from France.

They have continued to come despite the high fences built over past months to keep them from crossing, and despite Britain's refusal to accept the vast majority of them.

For children who may be accepted by the British government, a separate facility has been set up.

As the queue of mostly male adults formed in the morning fog outside a processing centre, some refused to accept that their dream of reaching Britain was over.

Hamid, 30, from Afghanistan, said he had been among those setting fire to shelters.

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

(Reporting by Matthias Blamont and Pierre Savary; Writing by Andrew Callus; Editing by Dominique Vidalon and Raissa Kasolowsky) ((andrew.callus.thomsonreuters.com@reuters.com; +33)(0)(1 49 49 51 30 ; Reuters Messaging: andrew.callus.thomsonreuters.com@reuters.net))