What Is a Part 35 Expert Witness Report and Why Does It Matter?

If you've ever been involved in a housing disrepair case — or spoken to a solicitor about one — you've probably heard the phrase "Part 35 compliant". But what does it actually mean? Why does it matter? And what happens if an expert witness report is not Part 35 compliant?

At Disrepair Claim Surveyors, we prepare Part 35 compliant expert witness reports for housing disrepair cases across England and Wales. In this guide, we're going to explain exactly what Part 35 is, why it exists, what it requires and how our reports meet its requirements.

What Is Part 35 of the Civil Procedure Rules?

Part 35 is a section of the Civil Procedure Rules (CPR) — the rules that govern how civil court proceedings work in England and Wales. It specifically governs the use of expert evidence in civil litigation, including housing disrepair cases.

Before Part 35 was introduced, expert witnesses were often seen as hired guns — experts who would say whatever the party instructing them wanted them to say. Courts were flooded with competing expert reports, each advocating for one side's position, making it very difficult for judges to get to the truth.

Part 35 changed all of that. It established the key principle that an expert witness's overriding duty is to the court — not to the party who instructed them. An expert witness must be, and must be seen to be, genuinely impartial.

What Does Part 35 Require?

A Part 35 compliant expert witness report must include:

• Details of the expert's qualifications and experience
• The literature or other material the expert has relied upon
• A statement of the range of opinion on any issue and the reasons for the expert's opinion
• A summary of the conclusions reached
• A statement that the expert has complied with their duty to the court
• A statement of truth

The report must also comply with any relevant Practice Direction 35 — the accompanying guidance that sets out the format and content requirements in more detail.

What Is a Single Joint Expert?

Part 35 also introduced the concept of the single joint expert (SJE). Rather than each party instructing their own expert and then fighting over whose report is right, courts can direct both parties to agree on a single expert who will inspect the property and report to the court.

In housing disrepair cases, single joint expert appointments are increasingly common — particularly in lower-value cases where the cost of two separate experts would be disproportionate. Our surveyors regularly act as SJEs, providing an impartial assessment that both parties can rely on.

"As a single joint expert, our duty is to the court. Our report reflects the facts as we find them — not what either side wants to hear. That impartiality is exactly what makes our reports so trusted by solicitors and judges." — Disrepair Claim Surveyors

Can an Expert Provide Expert Evidence Without Being Part 35 Compliant?

Technically, a surveyor can produce a report for use in legal proceedings without following Part 35. But courts will not treat such a report as expert evidence. It may be admitted as factual evidence, but it will carry significantly less weight and may be challenged or even excluded entirely.

For a housing disrepair claim to succeed, you need your surveyor's findings to be treated as credible expert evidence by the court. That means Part 35 compliance is not optional — it's essential.

How Our Reports Comply With Part 35

Every expert witness report we produce at Disrepair Claim Surveyors is prepared with Part 35 compliance at its core. Our reports include:

• Full details of the surveyor's qualifications, accreditations and experience
• A clear statement of the surveyor's instructions
• A description of the inspection methodology
• Factual findings presented clearly with photographic evidence
• Expert opinion on the cause, extent and remedy of each area of disrepair
• A range of opinion statement where relevant
• A signed declaration of compliance with Part 35 CPR
• A statement of truth

What Happens After the Expert Witness Report Is Produced?

Once your solicitor has the expert witness report, they can use it to support a claim. In many cases, the strength of a well-prepared expert report leads the landlord or their insurers to settle out of court. Where the case does go to court, our surveyor may be asked to attend and give oral evidence — something our team is experienced in doing.