Evidence and disclosure - Waiver of privilege

Learning Outcomes

This article explains legal professional privilege and the circumstances in which it may be lost or waived in civil litigation for SQE1. It details the two main categories of privilege (legal advice privilege and litigation privilege), the dominant purpose test, and the mechanisms of waiver (express, implied, and inadvertent). It examines collateral or subject-matter waiver, deployment-based implied waiver in statements of case, witness statements, and advocacy, and how courts apply fairness principles when determining the scope of any waiver. It reviews key Civil Procedure Rules relevant to privilege and disclosure (CPR 31.3, 31.14, 31.19, and 31.20) and their practical impact on inspection, redaction, and inadvertent disclosure. It also discusses ethical and procedural steps following inadvertent disclosure, professional conduct duties when receiving privileged material by mistake, and scenarios where privilege is lost other than by waiver (including the crime–fraud exception and loss of confidentiality/public domain). It provides an exam-focused framework for analysing problem questions, identifying when privilege arises, predicting when waiver is likely to be found, and advising on strategies to manage disclosure risks effectively.

SQE1 Syllabus

For SQE1, you are required to understand the practical implications of waiving legal professional privilege during the disclosure process in civil litigation, including recognising the types of privilege, how waiver occurs, and the consequences for the parties involved. Your knowledge should enable you to advise clients effectively and manage disclosure obligations correctly, with a focus on the following syllabus points:

• The distinction between legal advice privilege and litigation privilege.
• The different ways privilege can be waived: express, implied, and inadvertent waiver.
• The consequences of waiving privilege, including the potential scope of the waiver.
• The court's approach to disputes involving alleged waiver, particularly inadvertent disclosure.
• Relevant Civil Procedure Rules (CPR) concerning privilege and disclosure.
• How references to privileged material under CPR 31.14 and the “deployment” of advice in litigation can lead to implied waiver.
• Practical strategies to avoid inadvertent waiver, including electronic disclosure protocols and professional conduct duties.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. Which of the following best describes the 'dominant purpose' test in relation to privilege?
   1. It applies only to legal advice privilege.
   2. It determines if a communication's main purpose was for obtaining legal advice.
   3. It applies only to litigation privilege.
   4. It determines if a communication's main purpose was for conducting litigation.
2. A solicitor sends an email containing privileged advice to their client but accidentally copies in the opposing solicitor. What type of waiver might this represent?
   1. Express waiver
   2. Implied waiver
   3. Inadvertent waiver
   4. No waiver has occurred.

3. True or False: Once legal professional privilege is waived over part of a document, privilege is automatically waived over the entire document and related materials on the same subject.

Introduction

Legal professional privilege (LPP) is a fundamental right allowing parties to communicate confidentially with their lawyers without fear of those communications being disclosed to an opponent or the court. However, this protection is not absolute and can be lost through waiver. Waiver occurs when the party entitled to the privilege (the client) acts in a way that is inconsistent with maintaining the confidentiality the privilege is designed to protect. Understanding how privilege can be waived, intentionally or unintentionally, is critical for practitioners managing litigation and advising clients on disclosure.

Key Term: Legal Professional Privilege (LPP)
A fundamental right protecting certain confidential communications between a lawyer and client (legal advice privilege) or communications made for the dominant purpose of conducting litigation (litigation privilege) from compulsory disclosure.

Types of Legal Professional Privilege

Before considering waiver, it is necessary to briefly distinguish the two main types of LPP.

Legal Advice Privilege

This protects confidential communications made between a client and their lawyer for the dominant purpose of giving or receiving legal advice. It applies whether or not litigation is contemplated or pending. The definition of 'client' can be narrow, especially in a corporate context, potentially excluding communications with employees not tasked with seeking legal advice (Three Rivers District Council v Governor and Company of the Bank of England (No 5) [2003] EWCA Civ 474).

Only communications that are genuinely aimed at or within the continuum of legal advice are covered. Advice given in a non-legal capacity or general commercial guidance is unlikely to attract this privilege. Advice by non-lawyers does not qualify. Privilege extends to internal dissemination within a client organisation where necessary to implement or consider the legal advice, provided confidentiality remains intact.

Litigation Privilege

This protects confidential communications made after litigation has commenced or is reasonably in prospect. The communication's dominant purpose must be to conduct that litigation. This includes communications between the lawyer and client, the lawyer and a third party (e.g., an expert witness), or the client and a third party, provided the dominant purpose condition is met (Serious Fraud Office v Eurasian Natural Resources Corporation Ltd [2018] EWCA Civ 2006). If there are multiple reasons for creating a document, litigation must be the dominant purpose. The question is assessed from the standpoint of the person who procured the document, not necessarily its author.

“Litigation reasonably in prospect” requires a real likelihood of adversarial proceedings, not a mere possibility. Internal investigations undertaken because litigation is reasonably anticipated may qualify, but communications prepared predominantly for non-litigious purposes (e.g., purely compliance or commercial objectives) will not.

Key Term: Dominant Purpose Test
A test applied primarily to litigation privilege (and sometimes considered in relation to legal advice privilege) to determine if the main reason for creating a communication was for conducting litigation or obtaining legal advice. If the purpose was mixed, the litigation/advice purpose must be the dominant one for privilege to apply.

Mechanisms of Waiver

Privilege belongs to the client and can only be waived by the client, or by their lawyer acting with authority. Waiver can occur in several ways.

Express Waiver

This is a deliberate and intentional disclosure of privileged material to a third party or the opposing party. For example, a client might choose to reveal part of their lawyer's advice to support their case or during settlement negotiations.

Once privilege is expressly waived over a communication, it is generally waived permanently. Importantly, waiving privilege over part of a communication may result in waiver over a larger class of related documents concerning the same issue or transaction, if fairness requires it to avoid a partial or misleading picture (Great Atlantic Insurance Co v Home Insurance Co [1981] 1 WLR 529). This is often referred to as 'collateral waiver' or the 'cherry-picking' rule. Collateral waiver typically extends to documents necessary to understand the disclosed material properly, rather than “everything in the file”.

If a party wishes to deploy legal advice in open court or relies on its effect, consider whether the partial disclosure will trigger broader collateral waiver. Where feasible, parties may elect limited waiver in a specific context (for example, to a regulator), but should use clear terms to preserve privilege against other parties and proceedings.

Key Term: Collateral Waiver
A fairness-based extension of waiver that occurs when a party discloses privileged material on a topic. The waiver may extend to other privileged material on the same subject that is necessary to avoid a misleading or incomplete picture.

Key Term: Limited Waiver
A deliberate disclosure of privileged material for a specific, limited purpose (such as to a regulator), intended not to waive privilege generally. Whether limited waiver is effective depends on clarity of the terms and the context.

Practical point: Disclosing privileged content in open correspondence (as opposed to genuinely without prejudice communications) risks privilege being lost permanently and may have collateral consequences under CPR 31.14 (documents referred to in statements of case can be inspected).

Implied Waiver

Implied waiver occurs when a party acts inconsistently with the maintenance of confidentiality, even without intending to waive privilege. The most common scenario is where a party refers to the content or effect of privileged communication in their statement of case, witness statement, or submissions to the court.

Key Term: Waiver
The intentional or unintentional loss of the right to claim legal professional privilege, usually by disclosing the privileged communication or acting inconsistently with the confidentiality it protects.

If a party pleads, for example, "I acted as I did because my solicitor advised me to...", they put the content of that advice in issue. Fairness dictates that the opposing party should be able to see the advice to test the assertion. The court will consider whether the reference merely mentions the existence of advice or actually relies on its content. Only reliance on the content typically leads to an implied waiver.

References in advocacy or witness statements to the “effect” of advice (e.g., that counsel advised settlement was sensible) can constitute “deployment”. If deployed to justify conduct, fairness may require disclosure of the substance of the advice and related documents so the court can assess the assertion. By contrast, a purely factual statement that “advice was sought” without reliance will rarely waive privilege.

Where a party refers to or quotes from privileged documents in statements of case or witness statements, CPR 31.14 allows the opponent to seek inspection of the document referred to. The court will balance inspection rights against legitimate claims to privilege under CPR 31.19, but the mere fact of putting privileged content in issue strongly indicates waiver.

Inadvertent Waiver

This occurs when privileged material is accidentally disclosed to an opponent, often during the disclosure process (e.g., mistakenly including a privileged email in a disclosure list or bundle).

The CPR provide specific guidance (CPR 31.20). If a party inadvertently allows a privileged document to be inspected, the party who has inspected it may use it or its contents only with the permission of the court. The court will usually grant permission unless the inspecting party knew or should reasonably have known that the disclosure was a mistake (Al Fayed & Others v Commissioner of Police of the Metropolis & Others [2002] EWCA Civ 780).

Factors the court considers include:

• Was the mistake obvious (e.g., clearly marked 'Privileged and Confidential')?
• How quickly did the disclosing party act to correct the mistake upon realising it?
• Did the receiving party know, or should they have known, the document was disclosed in error?
• Would it be unjust to prevent the inspecting party from using the document?

Key Term: Inadvertent Disclosure
The accidental revelation of privileged material to an opposing party, often during electronic disclosure or large-scale document review.

Solicitors receiving documents they realise have been disclosed by mistake are under a professional duty not to read them beyond what is necessary to identify the mistake and must immediately notify the disclosing solicitor. They should refrain from informing the client of the content of the mistake (to avoid compounding the breach) and follow professional conduct guidance on returning or destroying the material.

Electronic disclosure (PD 31B) should include agreed protocols to minimise inadvertent disclosure risk—such as privilege filters, agreed key-word searches, deduplication strategies, redaction protocols, and a staged approach to inspection.

Worked Example 1.1

A solicitor is reviewing disclosed documents from the defendant. They find an email between the defendant and their lawyer clearly marked 'Legally Privileged - Advice on Settlement Strategy'. The email was listed in Part 1 of the defendant's disclosure list (documents available for inspection). What should the solicitor do?

Answer:
The solicitor should immediately stop reading the document, notify the defendant's solicitor of the apparent mistake, and return or delete the document as requested. They should not use the information contained in the email unless the court later grants permission under CPR 31.20, which is unlikely if the mistake was obvious and promptly addressed.

Worked Example 1.2

During disclosure, a claimant serves a list including communications with their expert witness prepared after litigation was contemplated. The defendant requests inspection. The claimant asserts litigation privilege. However, the claimant's witness statement explicitly summarises the expert's conclusions and states these were reached based on specific instructions provided by the claimant's solicitor. Is the claimant likely to have waived privilege over the instructions?

Answer:
Yes, likely an implied waiver. By deploying the substance of the expert's conclusions and referencing the solicitor's instructions in the witness statement, the claimant has put the basis of the expert's opinion (including the instructions) in issue. Fairness would likely require disclosure of the instructions referred to, to allow the defendant to understand the basis of the expert's stated conclusions.

Worked Example 1.3

A defendant’s defence pleads: “On counsel’s advice, the defendant terminated the contract early because continued performance would be unlawful.” The defendant refuses inspection of the advice, claiming it has only referred to the existence of advice.

Answer:
The reference likely amounts to “deployment” of the content. The defendant is using the advice to justify conduct and legal conclusions. Fairness would usually require inspection of the advice and any associated materials necessary to avoid a misleading picture (collateral waiver). Mere mention of advice would not waive privilege, but relying on its substance to prove a point generally does.

Worked Example 1.4

A claimant attaches a “position paper” to correspondence with the regulator that quotes parts of counsel’s advice. The claimant later argues the disclosure was “limited waiver” to the regulator only and resists inspection by the defendant.

Answer:
A limited waiver may preserve privilege in other proceedings where the purpose and scope of disclosure was clearly limited and confidentiality vis-à-vis other parties maintained. However, quoting substance of advice in open correspondence may be treated as deployment such that fairness requires inspection. The outcome depends on the clarity of limited waiver terms and whether the document was treated confidentially. Where in doubt, expect collateral waiver to extend to material necessary to avoid a misleading impression.

Exam Warning

Be careful to distinguish between mentioning the existence of legal advice and revealing its substance. Only revealing the substance is likely to lead to an implied waiver. Also, remember that privilege belongs to the client, not the lawyer; the lawyer waives it only on the client's authority.

Revision Tip

Focus on the dominant purpose test for litigation privilege and understand the concept of collateral waiver (fairness requiring wider disclosure after partial waiver). For inadvertent disclosure, remember the importance of prompt action by the disclosing party and the obviousness of the mistake.

Consequences of Waiver

Once privilege is waived, the communication or document loses its protected status.

• Disclosure: The material must typically be disclosed to the opposing party upon request. If a privileged document is referred to in statements of case, CPR 31.14 enables the opponent to seek inspection.
• Admissibility: It may become admissible as evidence in court.
• Scope: Waiver over part may extend to related privileged material (collateral waiver). This prevents a party from selectively disclosing favourable parts of privileged communications while withholding unfavourable related parts. The extension is limited to material necessary to avoid a distorted picture.
• Irrevocability: Waiver is usually final and cannot be retracted. Attempts to “claw back” after voluntary deployment are rarely successful.
• Costs and case management: Misuse of privilege claims (e.g., deploying advice and then resisting inspection) can result in adverse costs orders and case management sanctions.

Practical implications include carefully drafting statements of case and witness statements to avoid deploying privileged material inadvertently; using without prejudice channels appropriately; and ensuring redactions are properly reasoned where non-privileged documents contain sensitive irrelevant information (CPR 31.19; provide a privilege schedule explaining the basis of redactions).

Loss of Privilege (Other Than Waiver)

Privilege can also be lost in situations other than waiver.

Crime-Fraud Exception

Communications made for the purpose of furthering a crime or fraud are not protected by LPP. This applies even if the lawyer is unaware of the client's criminal or fraudulent purpose. The “iniquity” exception extends to serious wrongdoing. Where this exception applies, protection is removed, and the material may be ordered disclosed.

Public Domain

If privileged information ceases to be confidential because it has entered the public domain through other means, privilege may be undermined. Confidentiality is the basis of LPP. If the information is widely disseminated such that secrecy is lost, the privilege will normally not protect it in litigation against an opponent who can freely access it. However, the principle often stated as “once privileged, always privileged” still applies to the privileged status of documents in other contexts; each case turns on whether confidentiality in the specific litigation is genuinely lost.

Regulatory disclosures and limited waiver

Disclosing privileged material to regulators on a limited waiver basis may preserve privilege against third parties in other litigation if carefully documented and confidentiality is maintained. But if privileged content is quoted or deployed beyond the limited context, privilege may be treated as waived more broadly.

Worked Example 1.5

During standard disclosure, the defendant lists a privileged internal legal advice note in Part 2 of the disclosure list (privileged: inspection withheld). In the defence, the defendant pleads that “the claimant was warned on 12 January that performance would breach statute” and appends a letter to the claimant summarising the advice.

Answer:
Appending a summary that deploys the substance of legal advice risks implied waiver. The claimant may seek inspection of the advice under CPR 31.14 and argue collateral waiver over related documents necessary to contextualise the summary. The defendant should consider whether the defence can be re-pleaded to avoid deployment or accept that fairness requires inspection of the advice itself.

Worked Example 1.6

A large e-disclosure exercise uses agreed keyword searches. A subset of privileged documents passes the filter and is produced for inspection. The receiving party reads several before being notified of the error.

Answer:
Under CPR 31.20, the court will consider whether the receiving party knew or ought to have known the documents were privileged and disclosed by mistake. If the privileged nature was obvious or the mistake clear, the court may deny permission to use the content, and the receiving lawyer should have stopped reading and notified the other side. The speed and efficacy of remedial steps (claw-back protocol, privilege logs) will also be relevant.

Key Point Checklist

This article has covered the following key knowledge points:

• Legal professional privilege protects confidential lawyer-client communications (legal advice privilege) and communications made for the dominant purpose of litigation (litigation privilege).
• Privilege belongs to the client and can be waived expressly, impliedly, or inadvertently.
• Express waiver is a deliberate disclosure; it may trigger collateral waiver over related material if fairness demands.
• Implied waiver occurs when a party acts inconsistently with maintaining privilege, often by deploying the content or effect of advice in litigation (statements of case, witness statements, submissions).
• Inadvertent disclosure of privileged material requires prompt action to rectify; the court may permit use if the mistake was not obvious or the receiving party could not reasonably have known it was a mistake (CPR 31.20).
• CPR 31.14 enables inspection of documents referred to in statements of case; privilege must be properly claimed under CPR 31.19 and justified by a privilege schedule.
• Waiver of part of a communication may lead to collateral waiver over related material to ensure fairness.
• Privilege does not apply to communications made to further crime or fraud (iniquity exception), and it may fail where confidentiality is genuinely lost in the public domain.
• Limited waiver may preserve privilege in other contexts, but deployment in open litigation usually defeats privilege.
• Professional duties require stopping reading obviously privileged material disclosed by mistake and notifying the other side immediately.

Key Terms and Concepts

• Legal Professional Privilege (LPP)
• Dominant Purpose Test
• Waiver
• Inadvertent Disclosure
• Collateral Waiver
• Limited Waiver