A 23-year-old man has been arrested in connection with the investigation into the deaths of 39 migrants who were found dead in a refrigerated lorry container in Essex.

Essex Police said in a statement: "A 23-year-old man from Northern Ireland was arrested by officers from Thames Valley Police on behalf of Essex Police in the early hours of this morning on the M40 in Beaconsfield, Buckinghamshire, in connection with our enquiry into the deaths of 39 Vietnamese nationals in a lorry trailer found in Grays on 23 October.

"He was arrested on suspicion of conspiracy to traffic people and conspiracy to assist unlawful immigration, and remains in custody." 

The bodies of 39 Vietnamese nationals, including two 15-year-old boys, were found in the trailer in an industrial park in Grays, in the early hours of 23 October, shortly after the lorry arrived on a ferry from Zeebrugge, in Belgium.

The lorry driver, 25-year-old Mo Robinson, has appeared in court charged with 39 counts of manslaughter, conspiracy to traffic people, conspiracy to assist unlawful immigration and money laundering, and is expected to appear at the Old Bailey next week.

Extradition proceedings have been launched to bring 22-year-old Eamonn Harrison, from Mayobridge in Newry, Co Down, to the UK.

He appeared at Dublin's Central Criminal Court yesterday after he was arrested on a European arrest warrant in respect of 39 counts of manslaughter, one count of a human trafficking offence and one count of assisting unlawful immigration.

Detectives have also urged Ronan Hughes, 40, and his brother Christopher, 34, from Armagh, Northern Ireland, to hand themselves in.

They are wanted on suspicion of manslaughter and human trafficking.