Parliament of the United Kingdom, Criminal Law Act 1977 (1977)
“ Where a person is convicted by a magistrates’ court of a scheduled offence, it shall not be open to him to appeal to the Crown Court against the conviction on the ground that the convicting court’s decision as to the value involved was mistaken; and where a person is convicted before the Crown Court of such an offence, it shall not be open to him to appeal to the Court of Appeal against the conviction on the ground that the decision of the court which committed him for trial as to the value involved was mistaken. ”
