A medical expert who failed to disclose that he had trained the defendant on whose behalf he was giving evidence and that they had “worked together closely for a substantial period” has been criticised by the Court of Appeal.
Lord Justice Irwin said the “close connection” between expert witness Dr Andrew Molyneux and Dr Charles Barker, both radiologists, emerged only through cross-examination at the trial.
Irwin LJ said: “Our adversarial system depends heavily on the independence of expert witnesses, on the primacy of their duty to the court over any other loyalty or obligation, and on the rigour with which experts make known any associations or loyalties which might give rise to a conflict.
“Dr Molyneux failed to do so here, despite an express direction to that effect. Indeed, the omission of mention of papers co-authored with Dr Barker points in the other direction.”
Irwin LJ said the trial judge, Mr Justice Kenneth Parker, was “fully entitled” to take the view that, given the connection between the two men, the weight given to Dr Molyneux’s views should be “considerably diminished”.
Kenneth Parker J described himself as being “taken aback” that in an “unguarded moment”, Dr Molyneux referred to Dr Barker as “Simon”, the doctor’s middle name which he was usually known by.
The Court of Appeal heard in EXP v Barker  EWCA Civ 63 that a district judge, referred to as EXP, collapsed at home after suffering a brain haemorrhage in 2011, leaving her with a range of serious disabilities.
EXP had undergone an MRI scan of her brain in 1999, when she was a barrister and after experiencing “an episode of visual disturbance” in court.
Dr Barker, a consultant neuroradiologist, reviewed the brain scan. Following this, EXP’s was told by her consultant orthopaedic surgeon that “her brain scan was entirely normal”.
EXP argued that the scan was not normal, and there was an aneurysm, or bulge in the blood vessel, on a cerebral artery which should have been identified. Dr Barker argued that there was no aneurysm.
Irwin LJ said Kenneth Parker J held at the High Court in May 2015 that the 1999 scan indicated the presence of an aneurysm which a “reasonably competent” radiologist should have identified and reported.
Dr Barker appealed, arguing that the trial judge, having decided to admit the evidence of Dr Molyneux, failed to evaluate it on its merits and was wrong to hold that the expert had an “interest or bias in the outcome of the case”.
However, Irwin LJ said there was a “close connection” between Mr Barker and his principal expert witness, as the trial judge had made clear.
He quoted Kenneth Parker J, who described the connection as “lengthy and extensive”, and said Dr Molyneux had trained Dr Barker during his seven years of specialist radiology training, and in “particular had trained him for two and a half years as a registrar and senior registrar in neuroradiology, including the particular area of interventional radiology in which Dr Molyneux specialised and in which Dr Barker had a special interest”.
Irwin LJ went on: “It is clear that they had worked together closely over a substantial period”.
He said that since the connection only emerged during cross-examination at trial, it was too late for any alternative expert to be called. Following “argument and careful consideration”, the trial judge declined to completely exclude Dr Molyneux’s evidence.
“An important part of his reasoning was that if he did so, the appellant’s case must immediately fail.”
Irwin LJ went on: “In circumstances such as those arising here, the scrupulous expert in Dr Molyneux’s position should be pointing out the problem to the legal team well ahead of trial.
“No doubt that will usually be done in privileged communication. In many instances, a court will be cautious in drawing inferences for that reason. However, on the facts of this case, the judge found that Dr Molyneux ‘did nothing’.”
Lord Justice Irwin ruled that the trial judge was “fully entitled” to reject Dr Molyneux’s evidence as to the existence of the aneurysm and whether any “responsible, properly qualified” radiologist should have referred EXP for further investigation.
He dismissed Dr Barker’s appeal. Lady Justice Black and Lord Justice Henderson agreed.