One person has been charged with assisting unlawful entry into the UK after migrants were found in the back of a lorry at Newhaven ferry port in East Sussex on Friday, the Home Office has said.
Six people were taken to hospital after a major operation was launched following the discovery.
Local newspaper The Argus said the migrant were found in the back of a refrigerated lorry crossing from Dieppe in France.
No deaths have been reported by Sussex Police.
Two men were arrested in connection with the incident, one on suspicion of people smuggling and the other on suspicion of entering the UK illegally.
On Saturday, a spokesperson for the Home Office said: "An individual has been charged with assisting unlawful entry into the UK."
They did not name the person who has been charged.
They said Border Force, Immigration Enforcement and emergency services are continuing to investigate but that "while the incident is ongoing, it would be inappropriate to comment further".
South East Coast Ambulance said on Friday that it was called at 9.40am and "a range of ambulance resources" deployed.
Authorities were reportedly alerted before the ferry had docked.