Three would-be illegal immigrants were stopped from entering the country by UK Border Agency officials after they found hiding inside a lorry bound for Blackwood.
The two men and a woman, all from Eritrea, were found in Calais after officers working in the French port were alerted to their presence by sniffer dog.
Officers searched the Slovakian-registered lorry and found the three stowaways hiding among its load of plastic drinking cups.
After the find was made, at 4.05am on 18 February, the stowaways were handed over to the French border police and the vehicle was allowed to continue on its journey to Blackwood.
The Polish driver and the haulage company now 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, director for the South and Europe, UK Border Agency 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 illegally entering the country.
“As well as using detection dogs, our officers also use heartbeat detectors, carbon dioxide probes and detailed manual searches to find people who attempt to hide in vehicles.”