It's the end of a criminal trial and you have been convicted. The judge gave a sentence and you don't think it's fair. Can you appeal and get a different sentence?
If you want a lower sentence you must convince the appeal court that the sentence is "unfit" or unreasonable.
Judges have a wide discretion in sentencing; It is not good enough for you to believe that the judge made just any kind of a mistake. An appeal will succeed only if a judge made legal error, or did not apply sentencing principles correctly or if the sentence was beyond the appropriate range of sentence for the type of act that you committed. As you can see there are not a lot of reasons why an appeal on sentence should be allowed.
The grounds that could support an appeal are:
the sentence is excessive, given your background and the circumstances of the offence;
the sentence is illegal; or
there is an error in a principle of sentencing resulted in an unreasonable sentence.
Your appeal won't succeed unless you can show that one of these grounds apply.
If you're arguing that your sentence is excessive, you have to show that other decisions of the Court in similar circumstances gave much lower sentences. It's not enough to show that other cases gave a lower sentence – your sentence has to be quite out of the range. Judges know the law of sentencing and what is the normal sentence and so appeals on the basis of excessive sentence seldom succeed.
The Criminal Code is very complex and sets out the punishments that can be imposed; only punishments authorized by the Criminal Code can be imposed. Any sentence that isn't authorized by the Criminal Code is illegal.
Arguing a sentence is illegal is unusual because judges do know what is and is not a lawful punishment – I saw a judge correct a lawyer on a sentencing just last week (the lawyer suggested a two year sentence and the judge pointed out it had to be two years less a day to be legal). That said, judges are human and sometimes make mistakes. So, for example, if a judge makes a probation order for four years that is illegal. Under section 732.2(2)(b) of the Criminal Code a stand-alone probation order cannot be longer than three years.
The most common sentence appeals are based on the argument that the judge made an error in principle and did not impose a proper sentence. Again, judges seldom make mistakes here but it does happen from time to time.
The principles of sentencing that every judge must consider when imposing a sentence are:
To show the community's disapproval of the unlawful conduct,
To teach a lesson to the offender and to others who might commit a similar crime,
To protect the public,
To rehabilitation of the offender, and
To make amends for harm done to victims or to the community while promoting a sense of responsibility in offenders.
If a judge ignores or puts too much emphasis on one of these principles, the appeal court may consider changing the sentence. Additionally, when dealing with someone of aboriginal background, especially for less serious crimes, a further principle is that the court must consider not sending someone to jail, "with particular attention to the circumstances of Aboriginal offenders". So, if you have an aboriginal background and the court ignored that fact you may have a ground to appeal you sentence.
However, the fact that the judge has made an error in applying one of the principles of sentencing doesn't guarantee that the appeal court will change the sentence. You must also convince the court that the sentence is unfit. It is possible to get the right answer for the wrong reasons!