The Unduly Lenient Sentences scheme allows anyone to complain to the Attorney General that a sentence is too low. But it does not include serious domestic abuse, e.g. coercive control, for which there are frequent poor sentences which often seem to disregard Sentencing Council guidelines.
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The scheme has not kept up with the devastating effects of coercive control. Vera Baird QC commented: “The Sentencing Council makes clear that the huge breach of trust involved”, in this offence, “itself merits harsher punishment." https://www.shieldsgazette.com/news/police-chief-welcomes-new-sentence-rules-for-domestic-violence-1-8826066
Referring sentencing for this offence to the Court of Appeal would ensure senior judges reiterated the crime’s gravity and followed sentencing guidelines