A motorist heading home to Stourbridge, West Midlands, called police when he became suspicious of loud banging noises coming from the back of a German freezer lorry - which turned out to be carrying 12 illegal immigrants.
SWNS reports that Roger Furnell, 52, was stuck behind the lorry in a traffic jam on the M1, and saw the back doors moving as if they were being forced open.
Police asked him to follow the lorry while they dispatched a team of officers who directed it into Watford Gap services.
Mr Furnell then continued with his journey, but later found out that police had found 12 Middle Eastern illegal immigrants hiding in the back.
He told SWNS that he spotted the lorry at about 2.45pm last Friday. He said: "I was about to pull off the motorway for a nap when I heard the most deafening noise. It sounded like a train going over railway tracks.
"The noise continued and I became intrigued, so I managed to get behind the lorry when we started moving again, where I could see the doors flexing as though there was someone inside trying to get out."
He added: "I realised something wasn't right so I rang the police to report it."
Dead body found in plane's landing gear near Paris
Asylum seeker builds raft from twigs to sail to Australia