The Criminal Justice Act 2003 applicable in England and Wales, and to a lesser extent Scotland and Northern Ireland, implemented fundamental changes to the admissibility of evidence relating to character, in respect to defendants and others.
The Act is far-reaching, providing for the admissibility of previous convictions in support of a propensity to commit like-offences and untruthfulness.
[1] Common law rules in relation to the admissibility of bad character evidence have been abolished, with the existence of one exception.
[5] Bad character in relation to the alleged facts of the offence itself has always been admissible for obvious reasons (and is excluded by the definition).
[11] For instance, if a defendant had stated they were reluctant to use a gun, a previous conviction involving the use of firearms may be considered an "important matter in issue" in the case.