'Massive network' of European gangs smuggling migrants
UK immigration investigators have warned of a "big challenge" to tackle a "massive network" of criminal gangs trafficking people across Europe,
In two separate cases, three people smugglers have been sentenced after groups of Albanians were brought to England in small boats.
Eighteen were rescued from an inflatable which began sinking a mile-and-a-half off Dymchurch in Kent.
Seventeen others were discovered on a yacht at Chichester Marina in Sussex.
A court was told the smugglers at Dymchurch had pleaded guilty to being "hired boatmen": men who were paid £2,000 to transport the migrants but were not in the direct hierarchy of the smuggling operation.
Speaking to the BBC, David Fairclough led both investigations by the Home Office's Immigration Enforcement team.
"Organised crime groups work across borders, not just in the UK. They are working all over Europe, into the source countries. It is a massive network so it's a big challenge," he said.
"We face a severe threat of exploitation for illegal working, sexual exploitation and a vast amount is sponsored by organised crime groups.
"Because controls in ports are extremely strong and security has been enhanced, people smugglers are looking at more innovative ways to try to evade controls.
"The move into small craft recently is a new technique, but we are determined to remain one step ahead.
"And as these cases prove, we are onto this threat, taking it robustly."
A former senior immigration investigator has warned of the risk of sea tragedies, similar to those seen on the voyage to Turkey, Greece or Italy, taking place in the English Channel.
There is an "equal chance" of migrants drowning in the Channel as drowning in the Mediterranean, former chief inspector of borders and immigration, John Vine said.
"Clearly if this is now the start of something new, then really that needs to be reassessed and resources need to be put in," he added.
The Albanian migrants found in a catamaran in Chichester Marina had been brought across the Channel from Le Havre.
The National Crime Agency has said some migrants in France were willing to pay thousands of pounds to people smugglers, to risk taking them across the channel.
It also warned earlier this year that criminal gangs are targeting less busy ports.
Marinas along the south coast have been warned that boats could slip in unnoticed.
Chichester Marina said it worked with police on Project Kraken, an initiative encouraging maritime communities to report suspicions about criminal activity on the water.
But one boat owner there, Jim Prior, said many private boats could get in and out with few checks.
"There is no border control here. Once you get into the marina, people can just disperse, there's woodland and open country all around.
"They can walk to Chichester, be on the train and be away," he said.