Abuse of process in historic sexual abuse cases
In the recent case of R V Hallahan  EWCA Crim 2079 involving allegations of a sexual nature dating back to 1976, the court of appeal reaffirmed the view that delay will only lead to a stay of the case if real prejudice can be demonstrated.
Essentially, the delay must cause prejudice to the defendant which can be specifically demonstrated. Even if it can be established that records created at the time have been lost, this will not suffice in persuading the court to stop the case unless it can be shown that such material would have been probative to the issues in the case.
In doing so the court quoted a passage from the case of RD and essentially adopted the same reasoning:
“15. In considering the question of prejudice… it seems to us that it is necessary to distinguish between mere speculation about what missing documents or witnesses might show, and missing evidence which represents a significant and demonstrable chance of amounting to decisive or strongly supportive evidence emerging on a specific issue in the case. The court will need to consider what evidence directly relevant to the appellant’s case has been lost by reason of the passage of time. The court will then need to go on to consider the importance of missing evidence in the context of the case as a whole and the issues before the jury. Having considered those matters, the court will have to identify what prejudice, if any, has been caused to the appellant by the delay and whether judicial directions would be sufficient to compensate for such prejudice as may have been caused or whether in truth a fair trial could not properly be afforded to a defendant.”
In truth, staying any case for abuse of process has become more difficult in recent years and this line of authority seems in keeping with the modern approach. In short, unless you can demonstrate real prejudice even the loss of significant documents may not be enough to support a successful application.