On 29 July 2026, the President of the High Court Mr Justice David Barniville issued the much-anticipated Practice Direction HC 142 on the responsible use of generative artificial intelligence in court documents, which comes into operation on 1 September 2026.

Overview

The Practice Direction provides guidance on the Court’s expectations concerning the responsible use of Generative AI tools in litigation. The Court expressly recognises that GenAI tools may improve the efficiency of litigation and enhance access to justice. However, it also notes that “any use of GenAI tools must be appropriate and undertaken responsibly and with due care”. The risks associated with using GenAI tools are also highlighted, including inaccuracy, bias, factual errors, confidentiality, privacy and legal privilege issues.

Scope

The Practice Direction applies to all documents used in civil proceedings, (whether instituted before or after 1 September 2026). These documents include all pleadings, submissions, affidavits, witness statements and expert reports (collectively, “court documents”) which are prepared, produced or generated after the date of commencement. All persons involved in proceedings before the Court including parties, legal practitioners, witnesses, experts and third parties will be responsible for the content of their court documents notwithstanding the use of any GenAI tool.

Responsible use of GenAI

The Court must be able to rely on the integrity and accuracy of all court documents. The use of GenAI tools does not alter the obligations that legal practitioners owe to the Court including all existing professional and ethical obligations. All court users remain responsible for ensuring that content produced by GenAI is current, complete, accurate and relevant. Content produced using GenAI must be verified under human control and supervision. Any material submitted to the Court, which is produced using GenAI, should be:

• Fact-checked and proofread
• Edited and adapted to meet the circumstances of the case
• Verified so that any references to that case law, legislation, textbooks or articles actually exist and support the legal propositions attributed to them

Court users should ensure that evidential materials are authentic and represented, as fabricated materials must never be used or presented to the Court. This Practice Direction also applies to litigants in person and explicitly states that they are subject to the same obligations of accuracy and candour as represented parties.

Disclosure requirements for affidavits, witness statements and expert reports

The use of GenAI tools in preparing a court document does not of itself require disclosure. However, certain documents will now carry express declaration requirements. From 1 September 2026 onward, affidavits and witness statements must include a declaration that GenAI “has not been used for the purposes of generating the substantive content” of the document, including “altering, embellishing, strengthening, diluting or rephrasing the evidence set out”, and that the document reflects the deponent’s own “personal knowledge, recollection and evidence”. Purely administrative or ancillary uses of GenAI do not prevent this declaration being made.

Expert reports will also need to include a declaration that GenAI “has not been used for the purpose of generating the substantive content” of the report and that the report reflects the expert’s “own opinions, knowledge and evidence”. Where GenAI has been used for drafting, analysing, interpreting or generating the substantive content of the report, the expert must disclose the nature and extent of that use, so the Court and parties can assess the reliability, independence and evidential weight of the expert’s opinion.

Consequences of non-compliance

Parties who fail to comply with this Practice Direction may face sanctions including:

• Adverse costs orders
• Orders disregarding or rejecting court documents
• Where appropriate, the striking out of a claim or defence

Any legal practitioner who fails to comply, for example by citing non-existent authorities, may be referred to the Legal Services Regulatory Authority under the Legal Services Regulation Act 2015 or their professional body and a costs order may even be made against the legal practitioner personally.

Practical implications going forward

Legal practitioners must ensure that all court documents are drafted and verified in compliance with this new Practice Direction. Additionally, where applicable, clients and experts will need to be made aware of the new disclosure requirements for affidavits, witness statements and expert reports. The Practice Direction itself acknowledges that this technology is rapidly evolving and that it will be kept under regular review. Therefore, this developing area should continue to be monitored as the Practice Direction may be adapted in the future.

If you require further information, please contact a member of the Litigation, Dispute Resolution and Investigations Group or your usual Arthur Cox contact.