One of the stated objectives of the rule on exchange of witness statements (RSC Order 38 Rule 2A) is "the avoidance of a trial", and as a procedural device to speed up compromise settlements, it works well. Whether it helps with the fair and open presentation of evidence during the course of a trial is another matter.
The principle is that each party must serve on the other, at a fairly early stage in the proceedings, and within 14 weeks of the hearing of the summons for directions, written statements of the oral evidence which they will bring to trial. This enables each party to know how the other party will plead its case and prevents litigation by ambush.
However, witness statements have a peculiar status after exchange and before trial. They are not evidence until the witness confirms their contents in open court and they do not lose their status as privileged documents until that point (Balkanbank v Taher & ors). One party may choose not to rely on a witness statement that has been disclosed. The other party may not then pass that witness statement onto a third party save for the purposes of the action in which it was served.
A witness statement that has been served but not yet adduced in evidence may form the basis of an application for discovery of other documents provided that those documents are not themselves privileged. If they are, then the other party will have to wait until the witness statement is deployed in evidence at the trial before making an application for specific discovery.
For this and other reasons, where statements have been exchanged, it is difficult to give the courts a time estimate for the length of a trial. Some judges prefer a witness to be taken through their evidence in chief before they are cross-examined. Other judges simply take time out of the trial to read the statements for themselves. This can be frustrating when clients have come to court to see justice done.
Similarly, third-party observers of the trial such as journalists can no longer hear the evidence in full. Special provision has had to be made for witness statements to be made open to inspection, if the judge so directs.
Judges' procedures in dealing with all these issues will need to be sensible if trials are to remain fair and open.