Vrb phrs. A reference to goods that have been stolen. Used ironically to avoid revealing the real origins of the property. E.g."Being as they fell off a back of a lorry I'm selling them at half the price they are in the shops."
FALL OFF THE BACK OF A LORRY
Meaning of FALL OFF THE BACK OF A LORRY in English
Slang English vocab. Английский сленговый словарь. 2012