Police in France and Belgium have arrested 26 suspects as part of an investigation into human trafficking across Europe that was prompted by the discovery of 39 bodies in a lorry container in Essex.

The 39 Vietnamese nationals were found in a container which was parked at the Waterglade Industrial Park in Grays on October 23 last year.

An inquest heard that their medical cause of death was asphyxia and hyperthermia – a lack of oxygen and overheating – in an enclosed space.

Europol, the European Union’s law enforcement agency, set up an information-sharing operational task force following the discovery in Essex and on Wednesday it announced a series of arrests.

On Tuesday, houses in Paris and the Brussels area were searched, with 13 people arrested in France and 13 in Belgium, Europol said.

Those detained are suspected of being part of a criminal organisation trafficking Vietnamese nationals through Belgium and France to the UK.

Europol said 21 migrants were found and taken to safety, and three vehicles were seized, along with cash and electronic equipment.

The suspects are believed to have hidden their victims before routing them towards their final destination across the English Channel, the agency said.

Europol said it is likely that the network has transported up to several dozen people every day for several months.