When the other side wants to change expert are you entitled to their original expert’s reports and other documentation containing the substance of the expert’s opinion? This was the question considered in the case Allen Tod Architecture v Capita Property and Infrastructure Ltd ([2016] EWHC 2171) - a professional negligence claim by an architect against a structural engineer in the TCC. Unsurprisingly the claimant in that case resisted disclosure on the grounds that the documents and reports sought were privileged.

The claimant had grown exasperated by his expert’s delays and shortcomings and so turned to an alternative expert. At paragraph 32 of his judgment the judge set out the authorities and principles to be applied when considering whether to grant permission to a party to change expert:

(1) The court has a wide and general power to exercise its discretion whether to impose terms when granting permission to a party to adduce expert opinion evidence

(2) In exercising that power or discretion, the court may give permission for a party to rely on a second replacement expert, but such power or discretion is usually exercised on condition that the report of the first expert is disclosed (and privilege waived - see Vasiliou v Hajigeorgiou [2005] 1 WLR 2195)

(3)Once the parties have engaged in a relevant pre-action protocol process, and an expert has prepared a report in the context of such process, that expert then owes a duty to the Court irrespective of his instruction by one of the parties, and accordingly there was no justification for not disclosing that report as a condition for changing expert (seeEdwards-Tubb v JD Wetherspoon plc [2011] 1 W.L.R. 1373)

(4) The court's power to exercise its discretion whether to impose terms when giving permission to a party to adduce expert opinion evidence arises irrespective of the occurrence of any ‘expert shopping’. It is a power to be exercised reasonably on a case-by-case basis, in each case having regard to all the circumstances of that particular case.

(5) The court will require strong evidence of ‘expert shopping’ before imposing a term that a party discloses other forms of document than the report of expert A (such as attendance notes and memoranda made by a party's solicitor of his or her discussions with expert A) as a condition of giving permission to rely on expert B (see (BMG (Mansfield) Ltd v Galliford Try Construction Ltd [2013] EWHC 3183)

In the case of Allen Tod itself the judge found that there was no real reason for making a distinction between the expert’s final report, draft or provisional reports or other documents setting out his opinion: neither would have been discloseable if the expert had remained the claimant’s expert. He ordered disclosure of the original expert’s notes and preliminary report as a condition of permitting the claimant to rely on the new expert and he also ordered disclosure of any document in which the original expert had provided his opinion. To the extent any other material was contained in any such document, it was to be redacted before disclosure.