INTRODUCTION
In property disputes across England and Wales, expert evidence is frequently decisive. Whether the dispute concerns valuation, diminution in value, defects, dilapidations, boundary issues, or professional negligence, the court often relies heavily on independent expert opinion. In recent years, there has been a clear and consistent judicial preference for the appointment of a single joint expert in property disputes.
This long-form guide explains in detail the role, duty, and necessity of a single joint expert, why courts favour this approach, and how properly instructed expert evidence can significantly influence the outcome of a dispute. The article is intended for property owners, developers, solicitors, and other professionals seeking a clear understanding of best practice and compliance with the Civil Procedure Rules.
WHAT IS A SINGLE JOINT EXPERT?
A single joint expert is an independent expert jointly instructed by all parties to a dispute to provide expert evidence on defined issues. Instead of each party instructing their own expert, one expert produces a single report for the court.
The defining characteristic of a single joint expert is independence. The expert does not act for one party over another. Their overriding duty is to the court. This is a fundamental principle underpinning expert evidence in civil litigation and is critical to ensuring fairness and proportionality in property disputes.
THE LEGAL FRAMEWORK: CPR PART 35
The role of a single joint expert is governed by Part 35 of the Civil Procedure Rules and the accompanying Practice Direction. CPR Part 35 makes clear that expert evidence should be restricted to what is reasonably required to resolve the proceedings.
The rules expressly encourage the use of a single joint expert where appropriate. The court has wide discretion to direct that evidence on a particular issue be given by a single joint expert, especially where the issues are capable of being addressed by one suitably qualified professional.
Experts instructed under CPR Part 35 must comply with strict procedural and ethical requirements, including the provision of a statement of truth and confirmation of their understanding of their duty to the court.
THE OVERRIDING DUTY OF A SINGLE JOINT EXPERT
A single joint expert owes an overriding duty to assist the court on matters within their expertise. This duty overrides any obligation to the parties instructing or paying the expert.
Key elements of this duty include:
– Independence and impartiality
– Objectivity and transparency
– Providing opinion evidence based on facts and professional judgment
– Avoiding advocacy or partisanship
– Making clear where matters fall outside the expert’s expertise
This duty is not optional. Any perception that an expert lacks independence can significantly undermine the weight attached to their evidence.
WHY COURTS PREFER SINGLE JOINT EXPERTS IN PROPERTY DISPUTES
Courts favour the appointment of a single joint expert for several compelling reasons.
First, it reduces the risk of conflicting expert opinions. Competing expert reports can increase complexity, cost, and uncertainty. A single joint expert provides a unified opinion that assists the court in focusing on the real issues.
Second, it promotes proportionality. Property disputes can become disproportionately expensive if multiple experts are instructed. A single joint expert helps control costs and aligns with the overriding objective of the Civil Procedure Rules.
Third, it enhances efficiency. One expert report can narrow the scope of disagreement, encourage early settlement, and reduce the length of hearings.
Fourth, it supports fairness. Both parties have equal access to the expert and the same evidence, reducing the perception of bias.
WHEN IS A SINGLE JOINT EXPERT NECESSARY?
A single joint expert is commonly required in a wide range of property disputes, including:
Property valuation disputes, including matrimonial and probate matters.
Diminution in value claims arising from defects, damage, or development.
Dilapidations disputes at lease expiry.
Boundary and easement disputes.
Building defects and construction-related claims.
Professional negligence claims involving surveyors or valuers.
In lower value or technically focused disputes, courts are particularly likely to direct the use of a single joint expert.
EXCEPTIONS: WHEN SEPARATE EXPERTS MAY BE ALLOWED
Although the use of a single joint expert is encouraged, there are circumstances where the court may permit separate experts. This may occur where the issues are exceptionally complex, where different disciplines are required, or where fairness demands separate evidence.
However, parties should not assume that separate experts will be permitted. The burden rests on the party seeking permission to justify why a single joint expert would be inappropriate.
THE INSTRUCTION PROCESS
The instruction of a single joint expert typically involves agreement between the parties on:
– The identity of the expert
– The scope of instructions
– The questions to be addressed
– The documents to be relied upon
– Timetable and reporting requirements
Where agreement cannot be reached, the court may intervene and select the expert or restrict the parties to a shortlist.
QUESTIONS TO A SINGLE JOINT EXPERT
Following the service of the expert’s report, the parties are entitled to put written questions to the single joint expert. These questions must be proportionate, relevant, and for the purpose of clarification.
The ability to ask questions ensures procedural fairness while preserving the integrity of the single expert process.
COMMON PITFALLS AND RISKS
Common risks associated with single joint expert appointments include:
– Appointing an expert without appropriate experience
– Poorly drafted instructions
– Failure to define the scope of expertise
– Attempts to influence the expert’s opinion
Early professional advice can mitigate these risks.
IMPORTANCE OF EXPERT SELECTION
Selecting the right single joint expert is critical. The expert must possess:
– Relevant technical expertise
– Experience acting as an expert witness
– Familiarity with CPR Part 35
– The ability to produce clear, defensible reports
The credibility of the expert can directly influence the outcome of the dispute.
THE ROLE OF THE SINGLE JOINT EXPERT AT TRIAL
If required, a single joint expert may give oral evidence at trial. Their role remains to assist the court, not to advocate for either party. Courts often place significant weight on the evidence of a well-qualified and independent single joint expert.
STRATEGIC VALUE OF A SINGLE JOINT EXPERT
From a strategic perspective, a single joint expert can:
– Encourage early settlement
– Narrow issues in dispute
– Reduce costs exposure
– Increase predictability of outcomes
Proper use of expert evidence can be a decisive factor in dispute resolution.
CONCLUSION
The duty and necessity of a single joint expert in property disputes cannot be overstated. Courts increasingly expect parties to adopt a proportionate and cooperative approach to expert evidence. A properly instructed single joint expert enhances credibility, controls costs, and assists the court in achieving a fair outcome.
INSTRUCTING A SINGLE JOINT EXPERT
If you are involved in a property dispute, early advice is essential. We regularly act as single joint experts, providing independent, CPR-compliant expert evidence across a wide range of property matters.
Contact us today to discuss your dispute and to ensure your expert evidence is robust, independent, and effective.
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