A group of 15 children and six adults have been found in a refrigerated lorry in Newhaven, Sussex.
The people, believed to be from Vietnam, were hidden in a lorry full of sparkling water that arrived at the port on Thursday, the BBC reported.
A criminal investigation is underway and a Romanian man – thought to be the driver – has been charged with assisting unlawful entry into the UK.
The children did not need medical treatment, the BBC added, and have been transferred to social services.
An 18-year-old man and 27-year-old woman who were among the group have been removed from the UK, while the four other adults are in immigration detention centres.
The lorry had arrived from the French port of Dieppe.
Newhaven port provides cross-channel services for private passengers and commercial vehicles.