People smugglers have cut the cost of a place on a cross-Channel dinghy by overloading them with migrants, the National Crime Agency says.
The rate charged by criminals to reach the UK from France has fallen by about a third as demand has soared, it said.
Steve Dann, of the NCA, said boats were being “significantly overloaded” which “reduces the price and increases the risk significantly”.
Nearly 7,000 people have reached the UK in more than 500 small boats this year.
Matthew Long, deputy director of the NCA, said the crossings were a “chronic and enduring” issue, involving the exploitation of vulnerable people whose lives were being put at risk.
Co-operation between French and UK law enforcement had led to the arrest of 100 suspected people smugglers in the past two months, he said.
The Joint Intelligence Cell had also stopped about 500 migrants from making the dangerous crossing, he added.
Mr Dann said migrants in France were now being offered a place on boats for about €3,000.
There had been a “significant reduction in the amount people are paying”, down from about €4,500 at the start of 2020.
The nationalities of those making the crossings had also shifted over recent months, he said.
When the crossings began to increase in 2018 people were mainly from Iran and Iraq, but more recently there had been an increase in people from African countries, such as Sudan and Ethiopia, he said.
Some migrants who can not afford to pay smugglers attempt to “self-facilitate” by acquiring their own boats, but there is “a hardcore element of organised crime groups” who we running a “financial model to exploit vulnerable people,” Mr Long added.
He said social media companies needed to do more to stop smugglers advertise their services.
The NCA requested 1,300 accounts were removed between April and June, but social media companies refused to take down about 500.
“It is disappointing that too many of the accounts or pages we refer to industry are not taken down,” he said.
The NCA would be meeting “five of the major social media outlets” in coming weeks, he added.
On Tuesday, three people were arrested in the UK as part of an international operation which led to the arrest of ten people suspected of smuggling hundreds of people into the country in small boats.