British police have charged the 25-year-old driver of a container truck in which 39 people were found dead four days ago.
Maurice Robinson will appear at Chelmsford Magistrates Court on Monday charged with 39 counts of manslaughter, conspiracy to traffick people, conspiracy to assist unlawful immigration and money laundering.
The bodies were discovered on Wednesday after emergency services were alerted to people in a truck container on an industrial site in Grays, about 32km east of central London.
Police initially believed the dead were Chinese but Beijing said the nationalities had not been confirmed and on Saturday, a senior British police officer in charge of identification asked for help from Britain's Vietnamese community.
Chinese and Vietnamese officials are now both working closely with British police, the two countries' embassies have said.
Vietnamese Prime Minister Nguyen Xuan Phuc ordered government officials to help establish the identities of the victims and look into cases of Vietnamese citizens sent abroad illegally.
Father Anthony Dang Huu Nam, a Catholic priest in the remote town of Yen Thanh in northern central Vietnam's Nghe An province, 300km south of Hanoi, said he believed most of the dead were likely from Vietnam. He told Reuters he was liaising with family members.
"The whole district is covered in sorrow," Nam said, as prayers for the dead rang out over loudspeakers throughout the misty, rain-soaked town on Saturday.
"This is a catastrophe for our community."
Nam said families had told him they knew relatives were travelling to Britain at the time the container truck was on the road, and had been unable to contact their loved ones.
The British police officer in charge of identifying the victims, Detective Chief Inspector Martin Pasmore, said very few of the victims were carrying official identification and he hoped to identify the dead through fingerprints, dental records and DNA, as well as photos from friends and relatives.
Police have found more than 500 items within the truck including bags, clothing and mobile phones, that need to be assessed. Once a preliminary identification has been made, liaison officers will be deployed to support families.
Apart from the man charged, who will appear in court on Monday for an initial hearing, three other people are under arrest in Britain on suspicion of manslaughter and human trafficking. A fourth person is under arrest in Dublin.
How the victims came to be in the truck is not yet known.
British police sought to reassure anyone living in Britain illegally that they would not be investigated if they came forward to help with the identification.
"If you come to us, we will do all we can to put our arm around you and take you through this process, and establish as quickly as possible whether or not we have your loved involved in this tragic incident, and try and reunite you," Pasmore said.
With wires...
