``It is ludicrous,'' Lavinia Dingle said after learning her son's killer could walk free from jail in less than 12 months.

Coffs Harbour man Simon Dingle, 27, died after a stranger launched a senseless attack from behind at Deloraine in January. Mr Dingle was punched in the skull with such force his vertebral artery was severed.

The attacker _ a 17-year-old Parkham male whose identity is protected by law _ had pleaded guilty to manslaughter and was yesterday handed a three-year prison sentence in the Supreme Court in Launceston.

But he will be eligible for parole before this time next year.

``How cheap is life in this our country of Australia?'' Ms Dingle asked from her Coffs Harbour home yesterday.

``What sort of message are we sending to the youth of today?

``Certainly this sentence will not act as a deterrent _ and it's certainly not much of a punishment.''

Ms Dingle, accompanied by Mr Dingle's two younger brothers, had flown to Launceston last week to stand before the court holding a photograph of her son.

``Please don't allow my son to have died in vain,'' she pleaded after telling the court how her son's death had devastated her family.

That victim impact statement was yesterday acknowledged by Chief Justice Ewan Crawford when he

handed down the sentence.

``(Mr Dingle's) violent death has shocked and devastated the family,'' the judge said.

``His mother's victim impact statement made that very clear.

``All who heard it would have been deeply moved by it.''

But Ms Dingle says words are not enough.

``As a society we need to make a stand before it's too late,'' she said.

``Enough is enough.

``Apparently it will take a politician's son to be killed in this manner before the powers that be take a serious look at our antiquated legal system and make the necessary changes.

``Too late for my son.''