Editing Double jeopardy (section)

===== Pre-2003 =====

The doctrines of ''[[Peremptory plea|autrefois acquit]]'' and ''autrefois convict'' persisted as part of the [[common law]] from the time of the [[Norman conquest of England]]; they were regarded as essential elements for protection of the subject's liberty and respect for [[due process]] of law in that there should be finality of proceedings.<ref name="Benét1864p97" /> There were only three exceptions, all relatively recent, to the rules:

* The prosecution has a right of appeal against acquittal in summary cases if the decision appears to be wrong in law or in excess of jurisdiction.<ref>Magistrates' Courts Act 1980 ss.28, 111; Supreme Court Act 1981 s.28</ref>
* A retrial is permissible if the interests of justice so require, following an appeal against conviction by a defendant.<ref>Criminal Appeal Act 1968 s.7</ref>
* A "tainted acquittal", where there has been an offence of interference with, or intimidation of, a juror or witness, can be challenged in the High Court.<ref name="CPIA96">Criminal Procedure and Investigations Act 1996 s.54</ref>

In ''[[Connelly v DPP]]'' [1964] AC 1254, the [[Law Lords]] ruled that a defendant could not be tried for any offence arising out of substantially the same set of facts relied upon in a previous charge of which he had been acquitted unless there are "special circumstances" proven by the prosecution. There is little case law on the meaning of "special circumstances", but it has been suggested that the emergence of new evidence would suffice.<ref>''Attorney-General for Gibraltar v Leoni'', Court of Appeal, 1999 (unreported); see Law Com CP No 156, para 2.24</ref>

A defendant who had been convicted of an offence could be given a second trial for an aggravated form of that offence if the facts constituting the aggravation were discovered after the first conviction.<ref>''R v Thomas'' [1950] 1 KB 26</ref> By contrast, a person who had been acquitted of a lesser offence could not be tried for an aggravated form even if new evidence became available.<ref>''R v Beedie'' [1998] QB 356, Dingwall, 2000</ref>