French police say they have taken down a crime group which smuggled up to 1,000 migrants into the UK in just one year.

The Pierrefitte connection – as the gang is known – made up to 3 million euros loading people into trucks bound for Britain.

For the last 12 months police have watched the group closely, including bugging a bar in the Paris suburbs where members of the smuggling gang allegedly met to discuss their plans.

The investigation came to a head in a series of raids earlier this month with seven people arrested, a French police chief told the PA news agency.

The crime group smuggled migrants living in Paris or nearby out to the highway where they were loaded onto trucks in the south east of the capital.

The gang’s method reflects a shift of smugglers starting journeys farther and farther from the border in the belief that vehicles are less likely to be searched, Supt Jean Arvieu told PA.

He said he has seen evidence of migrants boarding trucks from as far away as Bordeaux – more than 500 miles from Calais.

Mr Arvieu is deputy chief of The Central Office for the Suppression of Irregular Immigration and the Employment of Untitled Foreigners (Ocriest), part of French Border Police.

Ocriest work includes targeting criminals trying to smuggle people into Britain, whether by road or on small boats.

Speaking to PA about the investigation into the Pierrefitte connection, he said: “They were operating at night.

“During one year of investigation we could count about 500 to 1,000 passages or attempts to cross the Channel.”

Those being smuggled had to pay 3,000 euros for a place aboard a truck and the crime gang is thought to have made between 1.5 million and 3 million euros from the operation.

Officers refer to the group as the Pierrefitte connection – a reference to its links to the northern Parisian suburb Pierrefitte-sur-Seine.

The migrants would have been living in squats in the French capital or the surrounding area and were mostly men aged between 20 and 35, Mr Arvieu said.

However, he added: “One night we could see a kid loaded in a truck and sometimes we have families. This is problematic.

“It shows that migrant smuggling by trucks to Great Britain is still a reality.”

With winter approaching and weather conditions getting worse, Mr Arvieu expects numbers of smuggling attempts in trucks to rise as small boat crossings become more dangerous.

Asked whether he thinks Brexit will have an effect on people smuggling via the Channel, Mr Arvieu said it was difficult to say.

Seven people have been arrested in connection with the Pierrefitte connection and three individuals have been remanded in custody while the investigation continues.