Mr Hughes unhooked the elastic cables from the trailer and was stunned to see the young man curled up in the trailer crammed with camping kit.
“You could have knocked me down with a feather when I opened the cover and there was a pair of feet.
“The guy was literally bent up like a pretzel round the camping chairs.”
The couple think the only time and place the man could have sneaked in was when they went to the supermarket before they checked in at the port.
They had to surrender their passports and driving licence and wait for hours until French police came to take the man away, and they missed their ferry.
The couple heard nothing for months when, on Saturday, a Border Force letter arrived saying they had not carried out standard checks on the trailer as soon as practicable before reaching immigration control and they owed a £6,000 fine.
“We’ve been sweating since May and I’ve not slept since we got the letter,” said Mr Hughes.