The 39 are believed to be victims of people trafficking. The bodies were discovered early on Wednesday morning. Initially it was thought that the trailer had entered the UK from the Republic of Ireland passing via the port of Holyhead, but now Zeebrugge is believed to be the port of departure.
The bodies of 39 people, 38 adults and a teenager, were discovered in the trailer. Their nationality is unclear. The lorry pulling the trailer originated in Northern Ireland, while the trailer is now thought to have entered the UK via the English port of Purfleet.
The driver from Northern Ireland has been arrested on murder charges.