Six would-be illegal immigrants were found trying to get into the country by hiding inside a lorry load of wheelie bins, the UK Border Agency has said.
The four men and two women from Vietnam were discovered in a Polish-registered lorry at the port of Calais in northern France after officials noticed the trailer's security cord had been tampered with.
Sniffer dog Jake was then used to search the vehicle, which was on its way to Dover, Kent.
The stowaways were handed over to French border police and the vehicle was allowed to continue on to its destination following the incident on July 21.
A spokeswoman for the UK Border Agency (UKBA) said the Polish driver and the haulage company each face a potential fine of up to £2,000 per stowaway if they are unable to prove they took steps to secure the vehicle.
Carole Upshall, UKBA director for the South and Europe, said: "This incident shows why we base UK Border Agency staff in France - to stop would-be illegal immigrants before they can reach the UK.
"Our strong presence in French ports like Calais helps protect the whole of the UK from people attempting to enter the country illegally.
"As well as using sniffer dogs, officers also use heartbeat detectors and carbon dioxide probes and physical searches to find people hiding in vehicles."