So much for family loyalty - police have released audio of a 911 call from a young boy reporting his dad for driving through a red light.

In the recording posted online by police in the Massachusetts city of Quincy, the pint-sized crimefighter can be heard telling a dispatcher about his father's alleged traffic offence.

"Um, daddy went past a red light," the boy says.

"He has a black truck. He was in a brand-new car, my mummy's car."

When the dispatcher asks what happened next, the boy, named as Robert, says his father committed the violation on the way to the car wash.

"Then he went past the red light," the boy says again.

The dispatcher asks to speak to the boy's father, who picks up the phone.

"Oh, no," the man says, with an embarrassed laugh. "I apologise."

"No problem," the dispatcher says.

The police department said the boy was six years old, but his father says on the call he is five.

Quincy Police did not pursue the alleged violation and no ticket was issued.

Presumably any fine would have been paid out of the boy's college fund.