fall off the back of a lorry

The phrase "fall off the back of a lorry" is a colloquial expression used mainly in British English. It is commonly used to refer to goods or items that have been acquired or obtained illegally or without proper authorization. The phrase implies that the items were stolen, smuggled, or acquired through some other illicit means. The origin of the phrase is rooted in the idea that stolen goods are often transported in the back of a lorry (truck), and so "falling off the back of a lorry" indicates that the goods were obtained unlawfully.