Half wit

[asperity]

Paddy McCoy, an elderly Irish farmer, received a letter from the Department for Work & Pensions stating that they suspected he was not paying his employees the statutory minimum wage and they would send an inspector to interview them.
On the appointed day, the inspector turned up.
"Tell me about your staff," he asked Paddy.
"Well," said Paddy, "there's the farm hand, I pay him £240 a week, and he has a free cottage.
Then there's the housekeeper. She gets £190 a week, along with free board and lodging.
There's also the half-wit. He works a 16 hour day, does 90% of the work, earns about £25 a week along with a bottle of whisky and, as a special treat, occasionally gets to sleep with my wife."
"That's disgraceful" said the inspector, "I need to interview the half-wit."
"That'll be me then," said Paddy!