The sinking of a migrant boat with the loss of 31 lives off the coast of France has once again raised concerns about the people-smuggling trade.
For years law enforcement on both sides of the English Channel have been playing a game of cat and mouse with criminal gangs as tactics change and evolve.
But despite millions of pounds spent and dozens of arrests, thousands of people continue to attempt the perilous crossing, with many paying huge sums to do so.
Fees for a spot in a dinghy headed for Britain can vary wildly, with reports ranging from 3,500 to 6,000 euros.
National Crime Agency (NCA) deputy director Andrea Wilson said: “We look to target and disrupt organised crime groups involved in people smuggling at every step of the route.
Much of this criminality lies outside the UK, so we have built up our intelligence-sharing effort with law enforcement partners in France and beyond.
One focus in the UK and elsewhere has been on disrupting the supply of dinghies and other vessels that could be used in Channel crossings.
The sale of dinghies in French towns has reportedly been banned, with kayaks seen withdrawn from sale at a Calais store.
However, one alleged smuggling gang targeted by police in the UK last year was thought to have been buying inflatable boats and engines from as far away as Germany and the Netherlands.
In the last couple of years, inflatable boats used in crossings have got bigger and bigger, now able to carry dozens of people – but not safely.
UK Home Secretary Priti Patel and the UK Government have repeatedly pledged to make the Channel route “unviable”, but the NCA previously said it views organised immigration crime as a “continuous threat”.
Earlier this month, an international operation saw 18 people arrested by French border police in the Calais, Le Havre and Paris regions of France.
More than 100,000 euros in cash and bank accounts was also seized.