<P> The British legal systems are based on common law traditions, which require: </P> <Ul> <Li> Police or regulators cannot initiate complaints under criminal law but can only investigate (prosecution is mostly reserved for the Crown Prosecution Service), which prevents selective enforcement--e.g., the "fishing expedition" which is often specifically forbidden . </Li> <Li> Prosecutors cannot withhold evidence from counsel for the defendant; to do so results in mistrial or dismissal . Accordingly, their relation to police is no advantage . </Li> <Li> Defendants convicted can appeal, but only fresh and compelling evidence not available at trial can be introduced, restricting the power of the court of appeal to the process of law applied . </Li> </Ul> <Li> Police or regulators cannot initiate complaints under criminal law but can only investigate (prosecution is mostly reserved for the Crown Prosecution Service), which prevents selective enforcement--e.g., the "fishing expedition" which is often specifically forbidden . </Li> <Li> Prosecutors cannot withhold evidence from counsel for the defendant; to do so results in mistrial or dismissal . Accordingly, their relation to police is no advantage . </Li>

Who came up with the separation of powers