The Romanian driver of the lorry has been arrested by the French border police who will investigate.
Dave Hutchinson, Border Force Deputy Director for South East & Europe, said: “The dangers of using refrigerated lorries and sealed tankers in this way are self evident. The consequences are potentially fatal."
In 2000, 58 Chinese immigrants died after being sealed into the back of a lorry which was stopped at Dover.
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Wednesday lunchtime's weather for the east of the region
Wednesday lunchtime's weather for the west of the region
There is a high risk from birch pollen during any good weather. Oak pollen is also on the increase.