Brad Kellson is pinned to the ground when a police officer twice his size knees him five times.

As officers drag him to a cell, he is wheezing and in clear and serious pain. Half of his ribs are fractured and he has a punctured lung.

The officers have a problem: how to explain what happened?

They charge Brad — whose most aggressive actions were to drunkenly, lamely grab at a body-worn camera and hold onto an officer’s leg — with assaulting police and resisting arrest.

The paperwork is completed about the time Brad is put in an ambulance and taken to hospital. He spends four days in intensive care.

Brad is no stranger to police violence and was first bashed by a cop when he was 12, but the assault at Blacktown Police Station is by far the worst of his 43 years.