Professional negligence: expert evidence

by | Aug 9, 2017 | Blog Posts

If you bring a professional negligence claim, you may need expert evidence to support your claim. This is particularly useful in cases where the alleged negligence relates to something technical. An expert witness should be able to give evidence to show:

  1. What the defendant did wrong;
  2. What a reasonable professional in the same circumstances would have done instead; and
  3. Potentially what loss was caused by the negligence.

Expert evidence is not required as often in claims against solicitors and barristers. However, if you are bringing a claim against someone such as a surveyor, it is likely to be extremely helpful. We will look at a 2015 case to show why expert evidence can be important; Wattret & Another v Thomas Sands Consulting Ltd [2015] EWHC 3455 TCC.


The claimants had a dispute with builders who had carried out works at their property. As a result of this dispute the claimants sought advice. However, instead of instructing solicitors to assist, they instructed chartered quantity surveyors (from the defendant company). The surveyors did have dispute resolution experience.

The dispute escalated and led to arbitration. The arbitrator however found in favour of the builders. The arbitrator ordered the claimants to pay a substantial amount by way of costs.

The claimants were not happy with this result or with the quantity surveyors who were representing them. They made numerous allegations against the defendant. These included the defendant’s failure to advise on obtaining after-the-event insurance. The claimants subsequently issued proceedings against the chartered quantity surveyors. They stated that if they had been properly advised by the surveyors, they would have saved around £1,200,000 in costs and damages.

Expert evidence

The claimants did not obtain expert evidence and tried to oppose the defendant’s application to obtain expert evidence also. The claimants argued that the case was similar to that of one against a firm of solicitors, where expert evidence would not usually be required.

It was argued in response that expert evidence should be given by a quantity surveyor with expertise in dispute resolution. The defendant argued that it was standard practice that an allegation of professional negligence should be supported by evidence by a relevant professional with the necessary expertise. The defendant said that this was not akin to a claim against a solicitor; solicitors and surveyors have different codes of conduct and training.


The judge found that expert evidence was necessary. He said that there was no hard and fast rule that expert evidence would always be required in professional negligence cases. For example, if the answer was obvious, there would be no need for an expert.

The court said it should judge the defendant to the standard, not of a solicitor, but of a reasonably competent quantity surveyor providing dispute resolution services. He noted that there may be differences between how a solicitor may act, and what a quantity surveyor might advise in a situation. In particular, a reasonably competent quantity surveyor may not be as familiar with after-the-event insurance as a solicitor would.

In order to control the amount of input the expert had in the case, the judge restricted the evidence to what was relevant. He noted:

“if unrestrained, there is a real risk that experts will provide swathes of commentary on each communication passing between the parties, giving their own slant or interpretation of what happened and what ought or ought not to have been advised… That must not happen in this case. If evidence of that sort is provided, the court will be able to make adverse orders for costs, even on an indemnity basis, against the party seeking to rely on such evidence.”


This case shows that while most professional negligence claims will require expert evidence, this is not an absolute rule. Further, if the parties use expert evidence, they should ensure that it only covers relevant points.
Our specialist professional negligence solicitors can assist you with claims against all types of professionals. Call today for a free no obligation initial consultation on 0800 988 7756.

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