Expert Witness Journal Issue 66 April 2026 - Flipbook - Page 9
A Cautionary Tale: Clinical Negligence
Experts and the Importance of
Understanding the “Bolam” test.
by Bond Solon.
A recent High Court decision highlights the critical
importance of expert witnesses in clinical negligence
cases having a sound understanding of the “Bolam”
test. While the test is not strictly determinative, a
lack of familiarity can signi昀椀cantly undermine the
credibility of their evidence.
•
Inadequate understanding of the Bolam test,
as revealed during cross-examination.
•
Failure to engage adequately with the
opposing expert’s views, leading the judge to
favour the defendant’s evidence.
4. What can experts learn from this case?
1. What is this new pilot scheme?
This case serves as a reminder that expert
witnesses in clinical negligence cases must not only
comply with the requirements of CPR Part 35 and
Practice Direction 35 but also demonstrate a clear
understanding of the legal principles underpinning
their role—particularly the Bolam test.
In Tarrant v Monkhouse [2025] EWHC 2576 (KB)
the claimant brought a negligence claim following
complications from bariatric surgery. Shortly before
trial, the pleadings were amended to narrow the
scope of allegations, resulting in a liability-only trial
focused on breach of duty and causation.
Our Clinical Negligence Essentials Part 1:
substantive legal principles and case law for the
expert witness course has been speci昀椀cally designed
for clinical negligence expert witnesses – ensuring
that they understand and are up to date with the core
legal principles that underpin clinical negligence
litigation. One of the key learning outcomes of the
course is breach of duty and standard of care, with
speci昀椀c reference to the legal tests applied in Bolam,
Bolitho and Montgomery.
Both parties instructed bariatric surgery experts.
During cross-examination, the claimant’s expert
was questioned about their understanding of the
“Bolam” test, which had been referenced in their
report.
2. The Outcome
HHJ Simon stated that the “inability of an expert
witness to recite the Bolam test by heart” is not
“determinative of the value” of their opinion.
Please visit the Bond Solon website for details of
their full training o昀昀ering for expert witnesses.
However, in this case, the claimant’s expert
demonstrated a lack of basic understanding of the
legal framework governing clinical negligence,
which signi昀椀cantly undermined his credibility. The
judge ultimately preferred the defendant’s expert
evidence.
www.bondsolon.com/expert-witness/
3. Speci昀椀c Judicial Criticisms
HHJ Simon identi昀椀ed several issues with the
claimant expert’s evidence:
•
Inconsistent terminology, making the report
di昀케cult to follow.
•
Lack of a coherent rationale for the opinions
expressed.
EXPERT WITNESS JOURNAL
7
APRIL 2026
