Criminal Appeal Act 1912

On an appeal against a conviction on indictment, the court may, either of its own motion, or on the application of the appellant, order a new trial in such manner as it thinks fit, if the court considers that a miscarriage of justice has occurred, and, that having regard to all the circumstances, such miscarriage of justice can be more adequately remedied by an order for a new trial than by any other order which the court is empowered to make.

Provision shall be made by rules of court for detaining the appellant until the fresh trial has terminated, or for ordering the appellant into any former custody.