A medical expert has been ordered to pay more than £50,000 for wasted costs after his report was used as the basis for an abortive negligence claim.

Recorder Abigail Hudson, sitting in Liverpool County Court, ruled that dentist Dr Chris Mercier had shown a ‘flagrant disregard’ for his duty to the court, putting a public body to considerable expense financing litigation that should never have been brought.

She said Mercier made no efforts to assist the court when he gave evidence, but was instead wilfully sticking to his theory irrespective of the questions asked or the evidence given. His input was ‘grossly unhelpful and wholly unreliable’, Hudson said, as it should have been obvious that he was not the appropriate expert to comment on the alleged negligence.

The court heard that a patient had brought a claim for dental negligence against Liverpool University Hospital NHS Foundation Trust, but withdrew the claim at the conclusion of the evidence. The surgeon who operated had removed only her lower molars, stating that he felt the remaining molar was restorable.

Mercier, a general dental practitioner, argued that no reasonable dental surgeon could have come to that conclusion and that the surgeon was negligent.

After the claim was dropped, the defendant sought £52,000 costs and submitted that Mercier should not have been giving evidence in the case. His representative argued that his expertise was well suited to the case.

However Mercier conceded that he had no experience of surgical removal of teeth under general anaesthetic since 2000. Recorder Hudson described Mercier’s evidence as ‘simply absurd’ and that his conclusions were ‘simply unsustainable’.

She added: ‘It is not clear to me that Dr Mercier has made any effort to understand the issues in this case. Dr Mercier repeatedly commented in his witness statements that he did not attempt to express a view on the surgical technique applied.

‘To make such references appears to imply that there is no difference between an oral surgeon and [general dental practitioner] beyond the moment in theatre. There is a wealth of difference in terms of role, experience and facilities. At no point does Dr Mercier make any attempt to analyse those issues.’