Three men were rescued from the back of an airtight lorry after calling police to say they were suffocating.
Officers launched a search for the vehicle on the M11 and A14 and it was eventually found at Brampton Services in Cambridgeshire on Wednesday.
The three men, who told officers they had been struggling to breathe, were safe and uninjured and were handed to the immigration services, police said.
The lorry is believed to have come from France.
Officers from both Essex Police and the Bedfordshire, Cambridgeshire and Hertfordshire roads policing unit were involved in hunting for the lorry, which was found at about 16:30 GMT.
“Stories like this may be distressing, but highlight that slavery and trafficking are real, and police need the public’s help,” a spokesman for the Cambridgeshire force said.
They asked people to look out for the “warning signs” including hearing banging from the inside of a lorry, things being thrown from lorries in order to grab the attention of other motorists, or groups of people trying to get in to lorries, or emerging from them.
The men who called police from inside the lorry were not hurt, officers said.
In October 2019, 39 Vietnamese migrants were found dead in a lorry trailer in Essex.
They had suffocated, and four men were jailed in January this year for their manslaughter.
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