The High Court has found that the defendants in this case did not have to disclose their previous experts' reports as a condition of obtaining permission for an extension of time to enable them to serve a report from a new expert: Vilca v Xstrata Limited  EWHC 1582 (QB).
Previous Court of Appeal authorities have established that the court can, and ordinarily will, require a party to waive privilege in a previous expert’s report as a condition of granting permission to adduce evidence from a different expert (see for example Edwards-Tubb v J D Wetherspoon  EWCA Civ 136, considered here).
The present case suggests that the reason for the change of expert may be a key factor in determining whether the court should attach such a condition – in particular whether there is any indication that the change is due to "expert shopping" (described by the court as the potentially disreputable practice of ditching an expert because he would not, for reasons good or bad, support a party's case) or will result in the court not having the full information. Here, there was no indication of that; the expert had resigned due to ill-health, and the judge was satisfied that disclosure of her draft report would not add anything in circumstances where each party would have evidence from an expert in which it had confidence.
Some other first instance decisions have taken what is arguably a different approach, requiring disclosure despite there being no strong indication of expert shopping – in BMG (Mansfield) Ltd v Galliford Try Construction Ltd  EWHC 3183 (TCC) (considered here) where the expert was almost 70 and did not want to continue acting, and in Allen Tod Architecture Ltd v Capita Property and Infrastructure Ltd  EWHC 2171(TCC) (considered here) where the party had lost confidence in the expert because he was unable to express his views clearly.
As a practical matter, therefore, parties who wish to change experts, and who need the indulgence of the court to be able to do so, should assume that they may need to disclose any previous reports (or draft reports or other documents setting out the previous expert's views) as the "price" of that indulgence – though the court may decide otherwise in an appropriate case, as this case demonstrates.
The underlying case concerned a group of Peruvian nationals claiming damages for personal injuries alleged to have been sustained in the course of a protest at a mine. The mine was owned and operated by the second defendant. The second defendant was an indirect subsidiary of the first defendant, a company registered in England.
The court made an order granting the parties permission to serve the written evidence of one expert each on Peruvian law. None of the relevant orders identified the expert who was to be instructed by either party.
The defendants had originally instructed an expert in the early stage of proceedings. This expert was replaced and a different expert was instructed by the defendants to prepare a report and appear for trial. This second expert withdrew at a late stage due to ill health. The defendants applied for an extension of time for service of expert reports to enable them to instruct a new expert.
Whilst this was in name an application for an extension of time to exchange expert evidence, the claimants accepted that the defendants should be able to call a new expert and an extension of time was needed. Rather, the substantive issue for the court to determine was whether the court should impose a condition requiring disclosure of the reports produced by the defendants' previous experts.
The High Court (Stuart-Smith J) rejected the claimant's submission that, as a condition of allowing instruction of the new expert, the reports produced by the defendants' previous experts needed to be disclosed.
In making its judgment, the court identified two questions it should consider. The first was whether the circumstances of the case gave rise to any power for the court to impose a condition. The court referred to Vasiliou v Hajigeorgiou  EWCA Civ 236, in which the court's previous order had not specified a particular expert and the defendant could have complied with the existing order to produce a report from a new expert in time. Thus the defendants did not require a further order, so no question of imposing a condition arose.
In the present case, the defendants needed an extension of time to prepare and serve the report from the new expert. This required the court's permission and thus the court's discretionary case-management powers were engaged. The court therefore had the power to impose a condition.
The second question for the court to consider was how it should exercise its case-management powers on the particular facts of the case. In answering this question, the court referred to previous Court of Appeal authority such as Beck v Ministry of Defence  1 WLR 2206, which showed that the court will usually require disclosure as the condition of granting permission for a new expert. In Beck the court commented:
"I do not say that there could never be a case where it would be appropriate to allow a defendant to instruct a fresh expert without being required at any stage to disclose an earlier expert's report. For my part, however, I find it difficult to imagine any circumstances in which that would be properly permissible and certainly, to my mind, no such circumstances exist here."
In the present case, however, Stuart-Smith J said these authorities did not change the fact that the court's discretion should always be exercised in accordance with the overriding objective. What they established was that the court would have regard to the possibility of undesirable expert shopping and the desire for the court to have full information before it (with the associated desire for the other party to be assured that the court's process is not being abused).
In the present case, the court accepted the defendants' evidence that, had the instructed expert not have been ill, she would have been their expert at trial. There was no evidence to suggest that the defendants were expert shopping.
Further, the court considered that there was also no evidence to suggest an abuse of process would result from instruction of the defendants' new expert. The new expert report would mean that the court and the claimants would have the full information in front of them in dealing with the dispute and there was no reason to consider that disclosure of the previous reports would add anything useful. In fact, in the judge's view, disclosure of another expert report would be a distraction and hindrance at trial and (given that the previous expert's report was in draft form) disclosure could give rise to distracting and costly arguments as to whether certain passages in the report represented the expert's final considered view.
The court noted that, even if there was no evidence of expert shopping or abuse of process, there may be circumstances in other cases which would justify the implication of the condition to disclose the previous experts' reports. In the present case, however, there was no other good reason to impose the condition.
The judge said he was referred by the parties to two first instance decisions, BMG and Allen Tod (referred to above). He described these as "useful examples of the application of existing principle", but said neither gave rise to any further point of principle that needed to be considered.