http://www.legislation.gov.uk/ukpga/2003/44/section/103/notesPoliceSentencingLegislationArrestPrisonsExplanatory Notes to Criminal Justice Act 2003Home OfficeKing's Printer of Acts of Parliament2020-04-20 44 20th November 2003 370 Section 103 relates to evidence of a defendant’s bad character that is admissible because it is relevant to an important matter at issue between the defendant and the prosecution (see section 101(1)(d)). Evidence might be relevant to one of a number of issues in a case. For example, it might help the prosecution to prove the defendant’s guilt of the offence by establishing their involvement or state of mind or by rebutting the defendant’s explanation of his conduct. Only prosecution evidence is admissible on this basis – section 103(6) – and the defendant may apply to have the evidence excluded under section 101(3). 371 Section 103(1)(a) makes it clear that evidence that shows that a defendant has a propensity to commit offences of the kind with which he is charged can be admitted under this head. For example, if the defendant is on trial for grievous bodily harm, a history of violent behaviour could be admissible to show the defendant’s propensity to use violence. Evidence is not, however, admissible on this basis if the existence of such a propensity makes it no more likely that the defendant is guilty. This might be the case where there is no dispute about the facts of the case and the question is whether those facts constitute the offence (for example, in a homicide case, whether the defendant’s actions caused death). 372 Where propensity is an issue, subsection (2) provides that this propensity may be established by evidence that the defendant has been convicted of an offence of the same description or category as the one with which he is charged. This is subject to subsection (3), which provides that the propensity may not be established in this way if the court is satisfied that due to the length of time since the previous conviction or for any other reason that would be unjust. 373 An offence of the same description is defined by reference to how the offence appears on an indictment or written charge. It therefore relates to the particular law that has been broken, rather than the circumstances in which it was committed. An offence will be of the same category as another if they both fall within a category drawn up by the Secretary of State in secondary legislation. An order establishing such categories will be subject to the affirmative procedure (see section 330(5)). The categories must contain offences that are of the same type (section 103(4)), for example, offences involving violence against the person or sexual offences. 374 Section 103(1)(b) makes it clear that evidence relating to whether the defendant has a propensity to be untruthful (in other words, is not to be regarded as a credible witness) can be admitted. This is intended to enable the admission of a limited range of evidence such as convictions for perjury or other offences involving deception (for example, obtaining property by deception), as opposed to the wider range of evidence that will be admissible where the defendant puts his character in issue by for example, attacking the character of another person. Evidence will not be admissible under this head where it is not suggested that the defendant’s case is untruthful in any respect, for example, where the defendant and prosecution are agreed on the facts of the alleged offence and the question is whether all the elements of the offence have been made out.