In January 2019, a two-year experiment began which affects the procedures for disclosure which have to be followed in most Business and Property Courts cases (ie in the Chancery Division, the Patents Court, the Technology and Construction Court, the Commercial Court and Circuit Commercial Courts, see r.57A.1; but not the Admiralty Court, the Intellectual Property Enterprise Court, cases assigned to the Shorter and Flexible Trial Schemes and other cases excepted from the pilot; see further, PD 51U para 1.4). I believe that this experiment will be a success and therefore, by the end of the year 2021, the pilot will become the standard procedure for most cases in all civil courts. What follows is an overview of the new system, concentrating on the changes from the old. There are also many ways in which the pilot duplicates or expressly applies the current system (Pt 31); for example, redaction, inadvertent disclosure and pre-action and non-party disclosure.


The pilot codifies the duties placed upon litigants and their lawyers (PD51U para 3, ‘Duties in relation to disclosure’) and confirms that these are continuing duties. The sanctions for failing to discharge them range from an adverse order for costs to committal for contempt of court (PD51U para 4). Three of the duties included in the list are obvious: obey orders, be honest, and conduct searches for documents in a responsible and conscientious manner. The other three are more exciting.

  • The duty to preserve relevant documents: As soon as persons know they are, or may become, parties to a claim, they must take reasonable steps to preserve relevant documents; suspend all deletion and destruction processes affecting such documents; and give all employees written notification identifying the documents or classes of documents to be preserved (PD51U para 4).
  • The duty to disclose ‘known adverse documents’: Once proceedings have commenced, the parties are duty bound to disclose any documents of which they are aware which adversely affect their case and are not privileged. This duty arises before any order for disclosure is made and continues throughout the proceedings. There is no obligation to search for adverse documents but if, by whatever means, parties become aware of such documents later, the duty to disclose it still binds them and is independent of any order for disclosure which may have been made (PD51U paras 3.1(2) and 3.4).
  • The duty to use reasonable efforts to avoid disclosing irrelevant documents: This is the sin of over-disclosing, ie disclosing a mass of irrelevant documents hoping that the really important documents will then get overlooked. In times past, the court could punish such behaviour, but, in practice, rarely did so. In some cases, of course, both sides were sinners.


The pilot requires parties to serve with their statements of claim an Initial Disclosure List of Documents (PD51U para 5). This list is limited to the key documents upon which the party has relied (expressly or impliedly) in support of its statement of case and the key documents that are necessary to enable opposing parties to understand the case they have to meet. A party making initial disclosure must also serve (but not file at court) copies of these key documents in electronic form. Initial disclosure is not required if the parties so agree, or if the court so orders, or if the volume of documents is large (over 1,000 pages, or over 200 documents).


Before the first case management conference (CMC), the parties must make known to each other whether they intend to request ‘Extended disclosure’ (PD51U paras 6–9). Extended disclosure may take the form of one or more of five disclosure models. These are different levels of disclosure.

  • Model A: Disclosure confined to known adverse documents, which duplicates the disclosure duty described above.
  • Model B: Limited disclosure, which duplicates the disclosure duty described above and also initial disclosure.
  • Model C: Request led search-based disclosure, which covers disclosures of specific documents or classes of documents (cf the current r.31.12 for ‘specific disclosure’) and also general disclosure which is limited to a particular issue or issues.
  • Model D: Narrow search-based disclosure, with or without narrative documents, a model which is similar to standard disclosure under the current r.31.6. A ‘narrative document’ is defined in PD51U, Appendix 1 as ‘a document which is relevant only to the background or context of material facts or events, and not directly to the Issues for Disclosure’ (as to which, see below). If the disclosure ordered does not require the search and disclosure of narrative documents, such documents must not be disclosed (unless of course they are ‘known adverse documents’; see above).
  • Model E: Wide search-based disclosure, which is similar to enhanced disclosure under r.31.7(d) (often referred to as train of enquiry documents or Peruvian Guano documents).


The court will make an order for extended disclosure only if it is satisfied that it is appropriate to do so in order to fairly resolve one or more of the issues for disclosure (PD51U para 6.3). To help the court to make this determination the parties must prepare, in advance of the first CMC in which extended disclosure is sought, a list of issues for disclosure and a disclosure review document (PD51U paras 7 and 10). For cases governed by the pilot, these documents replace the current disclosure report in form N263 and the electronic documents questionnaire. If the claimant is acting in person and a defendant is not, the court may request that defendant’s legal representatives to lead on the preparation and filing of the list of issues for disclosure and a disclosure review document (PD51U paras 7.9 and 10.10).


When deciding what, if any, extended disclosure to order, the court will have regard to estimates which the parties must provide as to the likely costs of giving the disclosure they propose and as to the likely number of such documents. If the cost budgeting scheme applies and both sides agree that it is impractical to complete the disclosure section of their budgets prior to the court’s decision on extended disclosure, they may notify the court that they have agreed to postpone this part of budgeting until after the first CMC. The court will later set a deferred deadline for this part of their costs budgeting (see generally, PD51U para 22).