Section 75 of the Criminal Justice Act (CJA) of 2003 overturned the principle in English law that a person cannot be retried for an offense of which he has been acquitted, recognizing advances in forensic science that uses modern analysis of DNA in adducing in evidence. The special plea of autrefois acquit can be overturned based on finding of compelling evidence after a previous acquittal of a suspect who can now be tried again for the same offense. The double jeopardy arises only after a lawful acquittal or autrefois convict of the accused for the first offense and these principles have allowed exceptions to the rule against double jeopardy developed by the courts. There is an analogous rule in common law courts based on the unreasonable splitting of the case when there is a severing of indictments which overrides the bar on the accused being retried for the same offense. This paper examines the difficulty of trying a defendant fairly in the English courts when the defense has pleaded an abuse of process and there is no clear overall argument for trial. This question needs an appraisal of legal ethics in criminal courts because a retrial of the accused on the same charge breaches the autrefois acquit doctrine, and severing of an indictment can cause the fair trial process to be undermined.