Police have launched a murder investigation after 39 bodies were found in the back of a lorry at the Waterglade Industrial Park in Greys, Essex.

The grim discovery was made in the early hours of this morning and all the victims were declared dead at the scene on Eastern Avenue.

The lorry is from Bulgaria and entered the country at Holyhead, North Wales – one of the main ports for ferries from Ireland – on Saturday.

Detectives have been on the scene since around 1.40am and confirmed that 38 of the victims were adults while one of them was a teenager.

They have taken a man, 25, from Northern Ireland into custody after arresting him on suspicion of murder.

It is thought the lorry will have entered Holyhead via Dublin.

Seamus Leheny, Northern Ireland policy manager for the Freight Transport Association (FTA), told PA: ‘There is a direct route to Holyhead from Dublin.

‘If the lorry came from Bulgaria, getting into Britain via Holyhead is an unorthodox route.

‘People have been saying that security and checks have been increased at places like Dover and Calais, so it might be seen as an easier way to get in by going from Cherbourg or Roscoff, over to Rosslare, then up the road to Dublin.

‘It’s a long way around and it’ll add an extra day to the journey.’

Prime Minister Boris Johnson tweeted: ‘I’m appalled by this tragic incident in Essex.

‘I am receiving regular updates and the Home Office will work closely with Essex Police as we establish exactly what has happened.

‘My thoughts are with all those who lost their lives & their loved ones.’

In a written statement, Home Secretary Priti Patel said: ‘I’m shocked and saddened by this utterly tragic incident in Grays. My heart goes out to all those affected.

‘Essex Police has arrested an individual and we must give them the space to conduct their investigations. Home Office immigration officials will be working closely alongside them to establish how this horrific event came to happen.’

Conservative MP for Thurrock Jackie Doyle-Price wrote on Twitter: ‘Sickening news of 39 people found dead in a container in Grays. People trafficking is a vile and dangerous business. This is a big investigation for Essex Police. Let’s hope they bring these murderers to justice.’

Cordons have been put in place around the industrial estate and are causing disruption throughout the area.

Prime Minister Boris Johnson has said he is ‘appalled’ and that his thoughts are with those who lost their lives and their loved ones.

Paige Wade, who drove past the scene at 4.15am, said: ‘I had just finished work while driving up Motherwell Way and all you could see was blue flashing lights, as I was driving past there was police tape to cordon off the start of Eastern Avenue.

‘I knew it was serious because of how many police cars and ambulances were there, but the police had parked their cars across the whole access of the road so you couldn’t see anything.

‘There’s always lorries around there as they park up there for the night, I couldn’t say whether I did or didn’t see the actual lorry in question.’

Chief Superintendent Andrew Mariner said: ‘This is a tragic incident where a large number of people have lost their lives. Our enquiries are ongoing to establish what has happened.

‘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.’

A cordon has been put in place and access to and from the Waterglade Industrial Park remains closed.