An angry husband in Australia has been jailed after catching his wife having sex with his brother in the back of the car and attacking her with a shovel while her mother sat in the front.

David McCulloch, 41, pleaded guilty to violent assault last week after he caught the pair having fun in a vehicle in Tasmania in March. The lawyer reported.

The bizarre ordeal was revealed during a Burnie Supreme Court sentencing hearing when a suspicious McCulloch tracked down his wife, Jacinta King, after she failed to answer her phone several times.

He found his wife of six years, with whom he shares four children, in the back of the vehicle with her brother, Jamie McCulloch, in a parking lot near his brother’s apartment building.

Shockingly, his own mother was sitting calmly in the driver’s seat when the pair were caught in the obscene act, the court heard.

Furious, McCulloch immediately began punching his brother in the chest and body before hitting his wife repeatedly in the head.

The spurned husband then grabbed a shovel from his car and began beating the couple with it, shouting “I’m going to kill them all”.

The court heard that at one point McCulloch smashed the shovel so hard that it broke in two.

His mother tried to intervene but was eventually pushed into a nearby trash can.

McCulloch’s wife and brother were taken to hospital with minor injuries from the attack.

At sentencing last week, the judge acknowledged the saga was “distressing” for McCulloch and described it as a “breach of trust” between family members.

“I accept that this was an emotional response to the circumstances you discovered,” said Judge Tamara Jago.

McCulloch pleaded guilty to a number of assault charges as well as possession of cannabis and possession of a firearm and ammunition.

He was sentenced to three years in prison.