A High Court ruling this week could mean fewer Australians in prison.

The sentencing of a 31-year-old man has created a new precedent for the consideration of disadvantaged upbringing. The High Court has found disadvantage caused by a person’s Indigenous heritage does not diminish over time and should be taken into account.

Lawyers for William Bugmy had successfully argued for his sentence over the assault of a prison guard to be reduced, based on the severe disadvantage that his shocking and violent upbringing has created.

The High Court ruling overturned an earlier New South Wales Criminal Appeals Court decision that his disadvantage had diminished over time – the High Court now says it does not.

Courts heard Bugmy had grown up in a home where alcohol abuse was perennial. He reportedly had to witness his father stab his mother 15 times.

Felicity Graham from the New South Wales Aboriginal Legal Service says Bugmy’s disadvantage is clear: “he hasn't spent an adult birthday in the community. He has problems with his mental health. He is a man who has suffered from the socio-economic disadvantage that exists in Wilcannia - limited education, he can't read and write.”

Ms Graham says the ruling has implication which could keep some Indigenous Australians out of prison.

“The High Court has directed sentencing courts to give full weight to the background factors relating to Aboriginality and social disadvantage and so this certainly could have an impact on the trends of over-representation of Aboriginal people in the criminal justice system,” she said.

Bugmy’s aunt travelled to Canberra for the hearing, saying she hoped it would have an effect on the entire community.

“You've got the Aboriginal disadvantage: it's there for health, work, employment - there's no employment,” Ms Bugmy said,

“It's not just about William and growing up in Wilcannia,”

“The outcome I'm hoping will be for all Aboriginal people.”