A dead man was among 35 immigrants found in a container at Tilbury Docks after crew were alerted by "banging and screaming".Police have launched a "homicide" investigation after the man was discovered with 34 sick children and adults hiding in a container on a P&O ferry.
At least seven of those treated at three different hospitals with "significant health problems" were children.
At a press conference at Tilbury Docks, Essex Superintendent Trevor Roe said the man's death was being treated as a crime.
Seven ambulances were sent to the scene and Basildon Hospital said on its Twitter feed that it was "responding to a major incident".
The East of England Ambulance service confirmed a hazardous area response team had also been sent to the scene.
Eighteen patients were taken to Basildon Hospital, nine to London Whitechapel Hospital and seven to Southend Hospital.