1. Where the condition of some material object is in issue or relevant to an issue (for example, the suitability of protective clothing), it should be produced for inspection by the court. Oral evidence can be given even where such articles are not produced,1 although failure to produce the object may lessen the weight that may be attached to the evidence.
2. Any material object that you may wish to use as evidence should be produced as an exhibit. Each exhibit should be identified wherever possible by a label or other mark of identification signed by the person who made the statement that refers to it and be sufficiently described in the statement to identify it. 2
3. Although it is always preferable to do so, there is no overriding duty on the prosecution to preserve evidence; sometimes the destruction of real evidence may be necessary for testing, etc. You may rely on photographs of real evidence that either cannot be taken to court or has been destroyed.3 Where an expert must examine an object and will leave it permanently altered, you should invite the defence to be present. Failure to do so will not exclude the evidence, but will lessen the weight which may be given to it. 4
4. Digital images printed through the use of a computer printer are now widely used in evidence. If the defence seek to challenge such evidence on the ground that it has been tampered with, you will need to put evidence before the court to show that the images have not been altered.
5. "Wet film" photography is less likely to be challenged, as there are unretouched negatives available to support the authenticity of the photographs, should any issue arise. Digital images are easily altered without those alterations being apparent. However, a proper audit trail showing that the integrity of the evidence has been preserved should be available to meet any defence challenge.
6. Once an article has become an exhibit, however, the prosecution may be entrusted with the duty of preserving and retaining it for trial or appeal. In such cases, there is a duty to: