The lorry arrived on a ferry from the Belgian port of Zeebrugge in October. AFP/VNA Photo

LONDON A British lorry driver on Wednesday pleaded guilty to the manslaughter of 39 people found dead in a refrigerated truck in southeast England.

Northern Ireland man Maurice Robinson, 25, was arrested shortly after the bodies of 31 men and eight women from Viet Nam were discovered in the truck in an industrial zone in Grays, east of London, in October.

The lorry arrived on a ferry from the Belgian port of Zeebrugge in the early hours of October 23, carrying the victims, who included two 15-year-old boys.

They died from lack of oxygen and overheating, according to post-mortem examinations.

Police charged five men, who appeared at a virtual hearing via Skype at the Old Bailey on Wednesday.

Robinson had already pleaded guilty to conspiracy to assist unlawful immigration and acquiring criminal property.

British Romanian Gheorghe Nica, 43, denied 39 counts of manslaughter while Romanian national Alexandru-Ovidiu Hanga, 27, denied a charge of conspiracy to assist unlawful immigration.

Northern Ireland man Christopher Kennedy, 23, has previously denied conspiracy to assist unlawful immigration while Valentin Calota, 37, was not asked to enter a plea to the charge of conspiring to assist unlawful immigration.

Prosecutor William Emlyn Jones told the court that human trafficking conspiracy charges were being dropped against Kennedy and Robinson. AFP