Criminal defence: expert witnesses
A defence team tests the evidence served against its client and puts the defendant’s own account and condition before the court. Both call for independent experts — whose duty, whichever side instructs them, is to the court alone.
The evidence
The disciplines defence instructions turn on
What the defence needs answered decides who it instructs: the defendant’s state of mind, the effect of alcohol or drugs at the material time, or whether an injury can bear the interpretation the prosecution puts on it.
Identify the question each report must answer, then agree scope, fees and timescales directly with the practitioner before the instruction is confirmed.
Find experts for the defenceJurisdiction
The context behind the instruction
In England and Wales, a publicly funded defence team ordinarily seeks the Legal Aid Agency’s prior authority before instructing an expert, and the expert’s fees are paid at the rates it prescribes. Scotland and Northern Ireland fund defence instructions through their own legal aid schemes, under their own criminal procedure.
Where the issue is the defendant’s capacity to stand trial, see fitness to plead; for the criminal courts more broadly, see criminal proceedings. The register does not determine legal issues or provide legal advice.
Report routes
Reports commonly considered
A records review lets an expert test the served medical and scientific evidence on the papers; a mental health assessment report puts the defendant’s own condition in evidence. Many defence instructions need one before the other is worth commissioning.
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Questions answered
Frequently asked questions
Which disciplines are instructed in criminal defence cases?
The discipline follows the question in issue - breach, causation, condition or future needs - and criminal defence cases often need more than one to tell the whole story. This page maps the specialties most commonly instructed, each opening the register already filtered, so a shortlist is one click away.
Can one expert deal with both breach and causation in a criminal defence case?
Sometimes, where both questions sit within a single specialty - but courts expect an expert to stay within their own expertise, so the two are often split across disciplines. The disciplines mapped above reflect the usual division of labour for this claim type.
What must a criminal defence expert report comply with?
In England and Wales, CPR Part 35 and its Practice Direction: the expert's qualifications, the material relied on, the basis of each opinion, the range of reasonable opinion where it exists, and the statement of truth. The other UK jurisdictions impose equivalent requirements, and the report follows the forum it is written for - a CICA application, a redress scheme or the Court of Protection each expect their own format.
Can an addendum or supplementary report be requested as the case develops?
Yes - new records, Part 35 questions or a changed prognosis are routinely dealt with by addendum rather than a fresh instruction, and continuity with the original expert is usually the efficient route. The register's report-type pages cover the formats, from screening and records review through to joint statements and addendum reports.