Migrants walk through a mud path of the "New Jungle" migrant camp in Calais, where thousands of migrants live in the hope of crossing the Channel to Britain.

AFP/Lille

A young French fisherman was among eight people arrested on suspicion of helping migrants cross the Channel to Britain in a high-speed inflatable boat, a judicial source said on Wednesday.

The man, who is thought to be around 20, was detained on Monday after being "caught red-handed, on the shore, while he was preparing a trip," said a police source.

A group of seven people suspected of being part of the smuggling network were later arrested, including Vietnamese citizens and an Albanian.

The network provided "guaranteed" journeys that lasted only 45 minutes to make the 90-kilometre crossing to Britain, said a judicial source in the northern city of Lille.

The fisherman had been smuggling migrants to Britain "for several months" on an inflatable Zodiac boat that could carry some 20 people at a time.

Migrants were charged between €10,000 and €12,000 euros ($11,000 to $13,000), the source added.

The boat would leave from a quiet beach near Dunkirk at night, and land on the British shore after a sometimes perilous journey across one of the world's busiest shipping routes.

"It's not without the risk. The boat almost capsized very recently," said the judicial source.

A customs patrol had to rescue the boat just over a week ago when it ran out of petrol on a return journey to Dunkirk.

The group of eight are currently being held in detention and could be charged by Friday, the judicial source said.

Money seized

A "large sum of money" was seized at the time of the arrests, the source said.

Interior Minister Bernard Cazeneuve confirmed the arrests on Europe 1 radio but said it was too early to discuss the details.

"We have dismantled a very large number of networks since the start of the year," he said.

"In France, it's nearly 200 networks representing 3,000 individuals, and in the Calais region it's around 30 networks, representing 700 individuals," he said, adding that they should be "severely punished".

Smuggling migrants across the Channel by boat remains relatively rare, according to the authorities.

In June 2013, eight Vietnamese migrants and two British smugglers were intercepted early in the morning near Calais as they drifted on a Zodiac boat.

The focus of police has tended to be on lorries crossing the Channel by ferry or on Eurotunnel trains.

Three suspected Iraqi smugglers were arrested on October 28 at a motorway rest stop in northern France as they tried to hide 26 migrants in heavy-goods lorries.

Although the figures pale in comparison to the numbers arriving in Germany and elsewhere, thousands of migrants have come through France this year, mostly from the Middle East and east Africa in the hope of reaching Britain.