Video report by ITV News Anglia's Russell Hookey
A murder investigation has been launched after 39 people were found dead inside a lorry in Essex.
Police were called to the Waterglade Industrial Park in Grays shortly before 1.40am on Wednesday morning.
Officers believe 38 of the victims were adults, while one was aged in their teens.
Police believe the lorry travelled from Zeebrugge in Belgium into Purfleet, and docked in the Thurrock area shortly after 12:30am this morning.
The tractor unit of the lorry is believed to have originated in Northern Ireland.
A 25-year-old-man from Northern Ireland has been arrested on suspicion of murder.
"This is a tragic incident where a large number of people have lost their lives. Our enquiries are ongoing to establish what has happened," Chief Superintendent Andrew Mariner said.
"We are in the process of identifying the victims, however I anticipate that this could be a lengthy process.
"We believe the lorry is from Bulgaria and entered the country at Holyhead on Saturday 19 October and we are working closely with our partners to investigate.
"We have arrested the lorry driver in connection with the incident who remains in police custody as our enquiries continue. I appreciate this cordon is going to disrupt the activity of local businesses in the area and we will work to ensure that disruption is kept as short as possible.
"We are working with Thurrock Council to mitigate against any impact our investigation scene will have locally."
Essex MP, and Home Secretary, Priti Patel, tweeted that she was "shocked and saddened" by the discovery, while Thurrock MP Jackie Doyle-Price said it was "sickening news."
Meanwhile, Prime Minister Boris Johnson vowed to "work closely" with Essex Police and said he was "appalled" by the incident.
Tony Fisher, a human rights lawyer from Essex, said refrigerated lorries are being used more often as they are harder to search.
Watch the full interview here: