Four men are due to go on trial this week for their alleged part in a people-smuggling plot linked to the deaths of 39 migrants.
The bodies of the Vietnamese nationals were discovered inside a lorry container shortly after it arrived in Purfleet, Essex, on a ferry in the early hours of October 23 last year.
Among the men, women and children were 10 teenagers, two of them 15-year-old boys.
An inquest has heard their medical cause of death was asphyxia and hyperthermia – a lack of oxygen and overheating – in an enclosed space.
Eamonn Harrison, 23, of Mayobridge, Co Down, Northern Ireland, is alleged to have driven the lorry trailer to the Belgian port of Zeebrugge before it sailed to Purfleet in England.
He is charged with 39 counts of manslaughter and one count of conspiracy to assist unlawful immigration along with alleged key player Gheorghe Nica, 43, of Langdon Hills, Basildon, Essex.
Valentin Calota, 37, of Birmingham, and Christopher Kennedy, 24, of Co Armagh, Northern Ireland, are charged with being part of the people-smuggling conspiracy.
All four defendants, who are in custody, deny the charges against them.
The trial at the Old Bailey before Mr Justice Sweeney is expected to open on Tuesday and go on for five weeks.