A fifth man has been arrested on suspicion of ferrying migrants to the UK from Belgium in boats.
The Albanian national was arrested by National Crime Agency (NCA) officers in Loughborough, Leicestershire, on Wednesday, the NCA said.
It followed a boat being seized by the NCA in Brightlingsea, Essex.
Derek Evans, senior investigating officer at the NCA, said: “The man arrested today is suspected of involvement in a plot to use small boats in a series of people-smuggling runs.
“Tackling organised immigration crime is a priority for the NCA and our investigation continues.”
The 44-year-old, from Leicester, is the fifth man to be arrested in connection with a gang which the NCA claims organised a series of people-smuggling runs to the UK from Europe last year.
Four men, believed to be part of the same operation, are set to appear in court later this month charged with assisting unlawful immigration.
Albanians Arsen Feci, 44 and Klodian Shenaj, 48, of Nottingham, and Banet Tershana, 51, of Hove, East Sussex, will appear at Nottingham Crown Court with 46-year-old Irishman Desmond Rice, of Aylesbury, Buckinghamshire, on March 29.