“To be As Happy As A Sandboy” means that you are in a state of joyous contentment.
This phrase passed into regular usage courtesy of Charles Dickens. In 1840 Dickens published The Old Curiosity Shop which includes an inn called The Jolly Sandboys that displayed a sign outside depicting three drunken sandboys. But what was a sandboy?
Dickens is known to have spent time in Bristol, which is referred to throughout The Pickwick Papers , published in 1836. Around that time it is recorded that the town’s landlords would spread sand on the floor of their establishments which would soak up any spillage, much in the same way as sawdust would be used in other places.
In Bristol, the Redcliffe Caves were full of sand and innkeepers would send boys off into the caves to provide them with a regular supply. These youngsters were paid partly in ale and consequently they were usually half-cut (drunk and therefore happy), hence Dickens’s inn sign and the origin of our phrase.