BBC licence fee collectors have been advised to be wary of customers using words like "shambles" and "useless" - they might be complaining about the broadcaster's service!
The advice comes in a new "idiot's guide" for the collectors.
It highlights what to look out for in letters, such as key words like "disgraceful," "appalling" or "furious."
It also says: "Remember, underlining of key words and phrases or the use of bold or capital letters designed to make certain parts of a letter stand out is also an indication of a complaint."
"I don't know about 'idiot's guide' - this is more like a fuckin' moron's guide," said a BBC insider last night.
"And what about the advice to those who collect the fee at the doorstep? 'A smack in the mouth probably means the customer is unhappy about something,' it says.
"Then it adds that if the customer looks like he's about to release his snarling Staffordshire Bull Terrier at you, he's not entirely happy for you to be there."