Skilled witnesses should not have a financial interest in the outcome of a personal injury case

  • Insight

16 November 2018

The role, payment and impartiality of skilled witnesses in personal injury cases has come into sharp focus in a judgment of the Sheriff Appeal Court in a case where one of the skilled witnesses was instructed on a ‘contingency fee’ basis, which effectively meant they had a financial interest in the outcome of the case.

The court has taken the opportunity to reiterate that where the evidence of a skilled witness cannot be said to be independent and impartial, it will not merely be given less weight, but will be inadmissible. The court also said that skilled witnesses may undertake work on a ‘contingency fee’ basis only in “very rare” cases. 

The background

The case concerned a road traffic accident in Glasgow in 2014. The pursuers had been injured in the accident and were seeking payment of damages from the defenders for those injuries. 

The expert medical witness (Dr AB) instructed for the pursuers was acting for them on a ‘contingency fee’ basis. This meant he would be paid for the three medical reports he had prepared for the case regarding the pursuers’ injuries only if the pursuers were successful in the case.

The defenders objected to Dr AB’s reports and to him giving evidence in the court hearing. This was on the basis that: (1) he was not independent and impartial; and (2) his reports were lacking proper analysis of medical concepts and how they applied to the facts of the current case, therefore no weight should be attached to his evidence.

The sheriff did not accept the defenders’ objections, found in favour of the pursuers and made the awards of damages. The defenders appealed to the Sheriff Appeal Court.

Duties of a skilled witness

It’s common in personal injury claims for a skilled witness to give evidence on the nature and extent of injuries suffered as a result of the accident. 

In the present case, the Sheriff Appeal Court summarised the duties of skilled witnesses when they are giving evidence in a civil case by referring to the principles outlined by Mr Justice Cresswell  in the case of National Justice Compania Naviera SA v Prudential Assurance Co Ltd (No 1) [1993].  These are that skilled witnesses must:

• ensure their evidence is not influenced by the fact that there is a court case on the issues pending or in process and,
• provide independent assistance to the court by way of objective, unbiased opinion in relation to matters within their expertise,
• ensure they do not act as an advocate for either party,
• state the material facts and assumptions upon which their evidence is based,
• make it clear when a particular question is outside of their expertise,
• state that the opinion is provisional only where insufficient data is available,
• communicate any change in his opinion to the other side and, if appropriate, to the court without delay and,
• provide all photographs, plans, calculations and relevant documentation referred to in the report to the other side at the same time as the exchange of reports.

Contingency fee arrangements

In its decision, the Sheriff Appeal Court held it could only be in “a very rare” case that the court would be prepared to consent to an expert being instructed under a ‘contingency fee’ agreement. This is because a ‘contingency fee’ arrangement gives the skilled witness an interest in the outcome of the proceedings, and therefore it may be said could colour their evidence.  In the present case, which concerned a low value personal injury claim, the instruction of a skilled witness on a contingency basis was not warranted.   


This decision serves as a stark reminder to skilled witnesses that in order to fulfil their duty to the court, they must remain impartial and independent.  Their purpose is to assist the court by providing information within their area of expertise, not to positively support the position of those instructing them. 

It also provides a warning to those instructing skilled witnesses to think twice before agreeing to instruct on a contingency basis – it may prove to be a false economy.  

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