A clear message has been sent around driving under the influence after the jailing of a 20-year-old, who killed one of his friends in a crash. 

Alexander Lucas Kerr has been sentenced to 27 months in prison after his friend died, and the other was severely injured. 

Kerr had cannabis in his system when he crashed his car in a semi-rural part of Havelock North on January 2. 

Criminal lawyer Steve Cullen told Ryan Bridge this is a stark warning of what can happen. 

He says the starting point's four to five years imprisonment for cases like this, so it's inevitable for someone to find themselves behind bars. 

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