Networks of people smugglers are working together to send “surges” of small boats across the Channel in an attempt to outmanoeuvre French patrol boats and reach the UK, the National Crime Agency has revealed.

Senior officers said they had evidence that smugglers were coordinating large-scale boat launches in a strategy to alleviate “pent-up demand”.

Steve Reynolds, head of the NCA-led Invigor task force, which tackles organised immigration crime, told the Observer: “There is evidence of some degree of coordination. There have been some quite large events, surges, where there have been nine or 10 boats.

“Depending on the availability of the boats, the weather and other factors that smugglers consider relevant, we believe there is a pent-up demand that gets released in a mass departure.”

Two weeks ago the Border Force intercepted the highest number of migrants attempting to reach the UK in a single day, with 86 men, women and children attempting the journey in small boats. A theory is that smugglers have adopted the same principle used by criminal gangs, who despatch a number of drug mules on to flights in the knowledge that some, but not all, will be stopped.

“There’s no specific intelligence to suggest that they operate like cocaine couriers, where they maybe send 10 people on the basis that two are going to get caught and the other eight get through, but there might be – we just don’t know for sure,” Reynolds said.

The closure of migrant camps in France provided opportunities to organised crime groups National Crime Agency

The tactic of organised smuggling gangs using small boats to send migrants across the Channel has been in operation for around a year with more than 1,300 people crossing the busy shipping lane in 2018.

Last Sunday, six men were taken to Dover, Kent, after attempting to cross the Channel in a dinghy, hours after four migrants were rescued from a stolen boat that got into difficulty off Calais. Days earlier, four small boats carrying 41 migrants were intercepted in the Channel.

However Reynolds rejected the notion that there was a “Mr Big” controlling the criminal trade. There was no evidence, he said, to suggest that an individual or gang was dictating proceedings from Iran, the starting point for the majority of migrants attempting the crossings. Similarly, there was little evidence that British-based gangs were involved, although Reynolds said that on occasions boats had left the UK, picked up migrants from the French coast and then returned.

Following a crackdown by the French authorities on the supply of boats in coastal regions, the National Crime Agency has seen a rise in dinghies being bought hundreds of miles from the French coast, even as far away as Germany.

Reynolds also said that migrants were now being brought directly to the French coast – usually the Boulogne-sur-Mer, Calais stretch – by smugglers who then forced them on to often dangerous boats. “Some of those that get on the boats are recruited away from the coast, brought in from further afield, maybe Germany, Belgium, and then bussed in and put on a boat,” he said.

Such techniques, he said, made it hard to quantify how many migrants were attempting to reach the UK and how many organised crime groups were involved in the trade.

However, the NCA believes the decision to destroy the huge migrant camp near Calais in 2016 has bolstered criminal operations. “The closure of migrant camps in France provided opportunities to organised crime groups, who facilitate a greater proportion of crossings,” states an NCA intelligence assessment.

Earlier this month, French police cleared a large migrant camp in Dunkirk, where about 1,000 people, including families with children, were living. The move has prompted fears it could spark a fresh surge of Channel crossings this autumn.

Another factor used by smugglers to drum up trade was Brexit, and Reynolds confirmed that smugglers used the outcome of the EU referendum and current stalemate as a “marketing tool” to try to hasten the decision of migrants to cross. He also said that NCA officers were deployed in countries such as Greece and Turkey to help crackdown on smugglers looking to exploit the Syrian civil war.