Pop band, Westlife singer’s claim over sleeve gastrectomy complications is likely to place surgical technique, causation and the interpretation of medical imaging under detailed expert scrutiny
The medical negligence claim brought by Westlife singer Mark Feehily against bariatric surgeon Nick Carter is likely to become an important example of the complexity of expert evidence in clinical negligence litigation.
Feehily alleges that a laparoscopic sleeve gastrectomy performed at Spire Portsmouth Hospital in Hampshire in August 2020 resulted in a series of serious complications, including a leak, abdominal infection and recurrent sepsis. He further alleges that insufficient stomach tissue was removed during the original procedure, leaving tissue which subsequently became infected.
Carter denies negligence. His defence accepts that a portion of stomach tissue remained following the operation and that a leak developed at the staple line, but maintains that the surgical decision was appropriate and that leakage is a recognised complication of sleeve gastrectomy. His case is therefore not simply about whether a complication occurred, but whether the complication was attributable to a breach of the appropriate standard of care.
The claim, issued in the High Court in 2025, is reported to be valued at more than £200,000. The litigation is expected to proceed initially as a split trial, with breach of duty and causation being considered before any assessment of damages.
The medical history
According to the reported court documents, Feehily experienced severe pain only days after the August 2020 operation and was subsequently admitted to hospital with complications which developed into sepsis.
He reportedly spent months in intensive care during the Covid-19 pandemic and required further surgery. His subsequent medical history included further infection, pneumonia, a chest infection and the development of a substantial incisional hernia.
The alleged consequences extended over several years. In May 2023, Feehily underwent a total gastrectomy, which is the surgical removal of the entire stomach. The singer then had to stepback from touring with Westlife, announcing in February 2024 that he would not continue touring with the group while dealing with his health problems.
For the purposes of the litigation, however, the fact that Feehily suffered serious complications does not itself establish negligence. The court must determine whether the defendant surgeon was in breach of his duty of care and, if so, whether that breach caused the injuries and losses alleged. That is where expert evidence becomes critical.
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Bariatric Surgeon and the Central Expert
The most important expert witness is likely to be a consultant bariatric or upper gastrointestinal surgeon with appropriate expertise in laparoscopic sleeve gastrectomy.
Such an expert may be required to address the standard of care applicable in August 2020 and to explain what a reasonably competent specialist bariatric surgeon would have done in the circumstances.
Among the issues likely to require expert opinion are:
- the accepted technique for performing a laparoscopic sleeve gastrectomy;
- the appropriate extent of gastric resection;
- the significance of gastric tissue allegedly remaining after the procedure;
- the technique used to create and secure the staple line;
- the recognised incidence and causes of staple-line leakage;
- whether a leak can occur notwithstanding reasonable surgical care;
- whether the operative findings were consistent with appropriate surgical technique;
- whether the postoperative course was consistent with a recognised complication or with a technical error; and
- whether the subsequent clinical deterioration can properly be attributed to the original procedure.
The expert’s task will not simply be to identify what went wrong medically. The expert must assist the court in determining whether the treatment fell below the legally relevant standard of care.
This distinction is fundamental in clinical negligence litigation.
A recognised complication does not necessarily answer the negligence question
One of the main issues reported in the defence is that leakage is a recognised complication of sleeve gastrectomy and occurs in approximately 1 per cent of procedures. This contention raises an important issue for expert evidence.
A complication can be recognised and unavoidable in some patients while, in another case, being caused by negligent treatment, thus, an expert may need to distinguish between: a recognised adverse outcome despite appropriate treatment, and an adverse outcome caused by a departure from accepted surgical practice.
The court will ultimately determine the legal question. The expert’s role is to provide the necessary specialist evidence from which the court can reach that determination.
Radiology experts
Radiological evidence is also expected to play an important role. Current reporting states that expert surgical and radiology reports are expected to be served in November. No individual radiologist has been publicly identified in the reporting examined for this article.
A consultant radiologist with relevant abdominal and gastrointestinal expertise could be required to review CT scans and other imaging obtained during the prolonged course of Feehily’s treatment.
The questions may include when evidence of a leak first became apparent, whether collections or abscesses were visible, the extent of intra-abdominal infection and how the radiological findings changed over time. Radiology may therefore become important not only in establishing what happened, but also in determining when it happened.
That distinction could be crucial to causation.
Infectious Disease and Sepsis Evidence
Given the allegations of recurrent sepsis, an infectious disease specialist or consultant microbiologist may also potentially be relevant to the wider evidential picture. Such evidence could address the nature and progression of the infections, the relationship between an abdominal leak and systemic infection, and whether subsequent episodes of sepsis can medically be linked to the original postoperative complication.
Whether such an expert is ultimately instructed will depend upon the issues pleaded and the evidence already available.
It is important to distinguish this from the experts currently publicly identified in connection with the case. The reports presently available specifically refer to forthcoming surgical and radiological expert evidence, rather than naming infectious disease experts.
Critical care and acute medicine
The reported history of prolonged intensive-care treatment may also create a need for expert evidence concerning critical care and the consequences of severe sepsis.
If the litigation requires the court to determine whether particular injuries or periods of incapacity resulted from the alleged original breach, rather than from later complications or independent medical events, a critical-care physician could potentially assist.
Again, this would depend upon the issues ultimately advanced by the parties.
The total gastrectomy and the chain of causation
Perhaps the most challenging evidential issue is the alleged causal chain extending from the 2020 operation to the total gastrectomy in 2023.
The court may have to consider a sequence along the lines of:
Sleeve gastrectomy → leak → abdominal infection → sepsis → further treatment and surgery → recurrent complications → total gastrectomy.
The longer the chain becomes, the greater the importance of expert evidence.
The claimant will need to establish more than the fact that the complications occurred after the original operation. The medical evidence must support the proposition that the relevant complications were caused by the alleged breach of duty.
The defence, conversely, may seek to distinguish between the original surgical procedure, recognised complications of that procedure, subsequent treatment decisions and later medical events.
This is precisely the type of issue on which a court may require a carefully reasoned expert opinion rather than retrospective speculation.
Could further experts become involved?
Depending upon the pleaded case and the claimant’s alleged losses, other disciplines could potentially become relevant.
A gastroenterologist could address the long-term consequences of the surgical complications and the absence of a stomach following the gastrectomy.
A nutrition specialist or dietitian could potentially address nutritional consequences arising from total gastrectomy.
A pain specialist might be relevant if chronic pain forms part of the claim.
A psychiatrist or psychologist could potentially be instructed if a psychiatric injury is alleged and requires expert assessment.
An occupational expert or other specialist may also become relevant if the claimant seeks damages for future employment or earning consequences.
However, none of these additional disciplines should be presented as having already been instructed unless that becomes clear from the court record or subsequent reporting.
What experts have been identified so far?
At the time of writing, public reporting does not identify individual expert witnesses by name.
What has been reported is that witness statements are due to be filed, followed by expert reports from surgical and radiology specialists in November 2026.
This is an important distinction for readers of Expert Witness Magazine. The identity of an expert, their specialty and their involvement in litigation should not be inferred merely because a particular specialty would logically appear relevant.
The publicly reported position is therefore:
Confirmed or publicly reported: expert surgical evidence and expert radiological evidence are expected.
Not publicly identified: the names of the individual experts.
Potentially relevant depending upon the pleaded issues: infectious disease, critical care, gastroenterology, nutrition, pain and psychiatric experts.
A case in which expert independence will matter
The Feehily litigation illustrates one of the fundamental principles of expert evidence: the expert’s duty is to the court.
An expert witness instructed by either party must provide an independent opinion based upon the evidence and their specialist knowledge. The expert is not an advocate for the claimant or defendant.
In a case such as this, that independence is particularly important because the medical history is extensive and the competing explanations for the patient’s deterioration may be complex.
The expert will need to distinguish fact from inference, identify the assumptions upon which an opinion depends and make clear where the medical evidence permits more than one interpretation.
The Probable Issues for the High Court (Researched with AI)
The forthcoming litigation is therefore likely to turn on several interconnected questions.
- Was the sleeve gastrectomy performed to an appropriate professional standard?
- Was the amount of stomach removed appropriate?
- Was the residual tissue clinically significant?
- Was the subsequent leak an unavoidable recognised complication or evidence of substandard surgical technique?
- When did the leak and infection develop?
- Were the subsequent episodes of sepsis causally related to the original operation?
- Could the later surgeries, including the total gastrectomy, reasonably be attributed to the original alleged breach?
- And what losses, if any, were legally caused by the defendant’s conduct?
These are questions upon which expert evidence may be decisive, although the ultimate findings of breach, causation and liability remain matters for the court.
An important case for medical experts
The case demonstrates why clinical negligence litigation can require a multidisciplinary evidential approach.
A surgeon may explain the operative technique. A radiologist may reconstruct the chronology from imaging. Other specialists may be required to address infection, intensive care, gastrointestinal consequences and long-term disability.
The court must then consider that evidence alongside the medical records, witness evidence and the parties’ respective cases.
For expert witnesses, the Feehily litigation is a useful illustration of the difference between a medical complication and actionable negligence — and of the evidential difficulty involved in proving causation when a postoperative complication develops into a prolonged sequence of further illnesses and surgical interventions.
