The most noted prerogative power that affect the judicial system is the prerogative of mercy , which have two elements : the granting of pardons and the granting of nolle prosequi . Pardons may eliminate the " pains , penalties and punishments " from a criminal conviction , though they do not remove convictions themselves . This power is commonly exercised on the advice of the Secretary of State for the Home Department ; the monarch have no direct involvement in its use . Exercises of this power may also take the form of commutations , a limited form of pardon where the sentences is reduced , on certain conditions . The granting of a pardon is not subject to judicial review , as confirmed by Council of Civil Service Unions v Minister for the Civil Service , but the courts have chosen to criticise its application or lack thereof , as in R v Secretary of State for the Home Department , ex parte Bentley . Granting nolle prosequi is done by the Attorney General of England and Wales ( or the equivalent in Scotland or Northern Ireland ) in the name of the crown , to stop legal proceedings against an individual . This is not reviewable by the courts , as confirmed by R v Comptroller of Patents , and do not count as an acquittal ; the defendant may be brought before the courts on the same charge at a later date .