Sentences could only get tougher for drivers who kill under the influence, as a 20-year-old's been sent to prison. 

Alexander Lucas Kerr has been sentenced to 27 months in prison, after a crash killed one of his friends and left the other in a wheelchair. 

He was found with cannabis in his system when he crashed his car in a semi-rural part of Havelock North in January. 

Criminal defence lawyer John Munro says Kerr doesn't qualify for home detention, despite heavy discounts to his sentence. 

He says if the starting point remains the same in a year, discounts could be capped at 40-percent. 

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