Cop guilty of assaulting drunk grandmother

A policeman has been found guilty of stomping on the neck of a drunk grandmother in a Cairns court.

Constable Alex Alexander pleaded not guilty to common assault after he allegedly stomped on Melanie Burgoyne's head or neck while restraining her at the Cairns watchhouse last year.

The grandmother was heavily intoxicated at the time and had been placed under arrest due to public nuisance.

While in the back of the police paddy-wagon, Ms Burgoyne used her bra strap in an attempt to choke herself. After she was escorted into the police station she flicked her bra at Mr Alexander, prompting him to restrain the woman.

Watchhouse officer Mark Webb and shift supervisor Sergeant Melanie Flynn both backed claims Constable Alexander struck Ms Burgoyne twice with his boot to the head or neck.

Mr Alexander maintained contact with the area was unintentional and had been an unfortunate accident.

Magistrate Jane Bentley said Mr Alexander lost control and over-reacted to the incident.

"The throwing of the bra was not such that it would induce an ordinary person to lose control.

"The defendant was not acting under any lawful justification," she said.