The case of Royal Marine Sgt. Alexander Blackman has been submitted to the Criminal Cases Review Commission. The way the submission was made -- i.e., very publicly -- has itself become a matter of contention, as this comment and string from The Herald indicates. The CCRC can refer the case to the Court Martial Appeal Court for further review.
Sgt. Blackman's sentence was previously reduced from 10 years to 8 on appeal.