Expert Witness Journal Issue 66 April 2026 - Flipbook - Page 96
Van Oord v Allseas: A Decade On and
Still a Warning For Quantum Experts
by Paul McArd, Managing Director at Accura Consulting.
It is now more than ten years since Van Oord UK Ltd
v Allseas UK Ltd was decided, but I still see the same
mistakes the court exposed in that case appearing
in quantum reports today.
Assumptions were hidden rather than tested
The expert valued the claim on one basis only,
namely the claimant’s full case. He refused to
provide alternative valuations based on di昀昀erent
factual assumptions, despite encouragement from
the court to do so. When key assumptions failed
under cross examination, the valuation collapsed
because there were no alternative 昀椀gures (para 83).
The judgment matters because the court did not
merely criticise an expert’s approach. It rejected the
claimant’s quantum evidence in full and explained,
step by step, why it could not be relied upon. Those
reasons remain directly relevant to any quantity
surveyor acting as an expert witness.
In my experience, this is one of the most common
and most avoidable errors. Courts are not asking
experts to predict outcomes. They are asking them
to show consequences.
Looking back, the case reads like a checklist of what
goes wrong when experts drift away from their
proper role.
Actual loss was never addressed
One of the most telling criticisms was that the expert
never tested the claim against actual cost. He did
not ask whether any real loss had been su昀昀ered at
all. The judge said this created the impression that
the claim was a try on rather than a compensatory
exercise (para 84).
What Went Wrong?
The expert accepted the claim instead of
analysing it
The court found that the quantum expert took
the claimant’s pleaded case at face value. He did
not test it against the contemporaneous records
that supported or undermined it. Rates were
adopted because they were said to have been agreed
elsewhere, not because they had been independently
assessed (para 81).
Whatever the contractual mechanism, actual cost
remains a critical sense check. Ignoring it weakens
credibility immediately.
The evidence unravelled under cross examination
From an expert perspective, that is the 昀椀rst mistake.
Once you start with the claim rather than the
evidence, everything that follows is compromised.
As cross examination progressed, the expert
conceded error after error, many of which had
already been identi昀椀ed by the opposing expert
months earlier. Eventually he accepted that he was
not happy with any of his reports. The judge said
that once an expert disowns their own work, the
court cannot sensibly rely on it (paras 85 to 86).
Only one side of the evidence was considered
The judge was clearly troubled by the fact that the
expert prepared his report by reviewing only the
claimant’s witness statements. He did not engage
with the opposing evidence at all. In some instances,
disputed assertions were lifted directly into the
report as if they were established facts (para 82).
That moment ended the evidence. Once con昀椀dence
is lost, it is not recovered.
The schedules were not truly the expert’s work
At that point, independence has already been lost.
An expert cannot assist the court if they only look
in one direction.
EXPERT WITNESS JOURNAL
The court was also critical of schedules appended to
the report that the expert had not prepared and had
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APRIL 2026
