Duty
A radiologist ordinarily assumes a duty of care when accepting responsibility for an examination, procedure, or report.
Medicolegal fundamentals
Medicolegal Fundamentals
The legal principles that govern radiological practice and clinical negligence.
To establish clinical negligence in radiology, a claimant must prove that a duty of care was breached, and that this breach directly caused actionable harm.
This page sets out foundational legal principles. Detailed legislation, professional standards, and recent case law are explored separately.
Written for radiologists, lawyers, NHS legal teams and expert witnesses. Last reviewed October 2026
The structure of a clinical negligence claim
Duty, breach, causation and damage must be considered separately.
Part I
Legal framework
The Elements of a Clinical Negligence Claim
An adverse clinical outcome, reporting discrepancy, or missed abnormality does not automatically establish negligence. On the balance of probabilities, the claimant must prove duty, breach, causation, and compensable harm.
Breach
The core test is whether the radiologist exercised the reasonable skill and care expected of a competent practitioner undertaking that work at the time.
Causation
The claimant must demonstrate that, but for the breach, the injury or materially worse outcome would probably have been avoided.
Damage
Negligence is not actionable without injury or loss. A reporting error with no clinical consequence will not support an award of damages.
Part II
Core authorities
Bolam v Friern Hospital Management Committee
[1957] 1 WLR 582
Professional practice is not negligent if it accords with a responsible body of medical opinion.
Principle
The law acknowledges a range of acceptable professional practice. A clinician is not negligent merely because a peer would have acted differently.
Radiology
Divergent interpretations often fall within a permitted range of practice. Liability turns on whether original reporting fell outside responsible standards, not simply whether an abnormality can be seen retrospectively.
Bolitho v City and Hackney Health Authority
[1998] AC 232
Professional opinion must withstand logical analysis; courts are not bound to accept expert testimony simply because a body of practitioners supports it.
Principle
Supporting opinion must be reasonable, reasoned, and capable of balancing material risks and benefits.
Radiology
Experts must explain why a report was defensible given the images, protocol, clinical context, and standards of the era. Assertion alone is insufficient.
Muller v King's College Hospital NHS Foundation Trust
[2017] EWHC 128 (QB)
In pure diagnostic and interpretation cases (such as radiology, histology, and ECGs), the traditional Bolam deference to a "responsible body of opinion" has restricted application when deciding whether an anomaly was visible.
Principle
The court must determine as a matter of fact whether what is visible on the image or slide demonstrates a clear reporting error, distinguishing objective perceptual omissions from matters of genuine clinical judgment or opinion.
Radiology
A failure to identify a plain, conspicuous abnormality falls outside acceptable standards of care, regardless of whether a minority of peers might miss it.
Barnett v Chelsea and Kensington Hospital Management Committee
[1969] 1 QB 428
A breach establishes liability only if it actively caused the injury, evaluated through the conventional “but for” test.
Principle
If the injury would likely have occurred regardless of the breach, factual causation is not established.
Radiology
Identifying a missed finding is insufficient; the claimant must prove that a competent report would have prompted action preventing or reducing the harm.
Gregg v Scott
[2005] UKHL 2
English law rejects the doctrine of "loss of a chance" for medical-negligence claims concerning physical injury and reduced life expectancy.
Principle
A claimant must prove on a balance of probabilities (greater than 50%) that a delayed diagnosis caused a worse outcome, rather than simply proving that a delay reduced their statistical chance of survival.
Radiology
In oncology delays, proving that a missed tumour reduced survival odds from 51% to 40% succeeds, whereas a drop from 45% to 30% fails because the baseline probability of survival was already below 50%.
Montgomery v Lanarkshire Health Board
[2015] UKSC 11
Clinicians must take reasonable care to ensure patients are informed of the material risks of recommended treatments and any reasonable alternatives.
Materiality
A risk is material if a reasonable person in the patient's position would attach significance to it, or if the clinician should reasonably know that this specific patient would do so.
Radiology
This duty is critical in interventional procedures, requiring consent discussions tailored to the individual patient regarding material risks and options.
Part III
Application to radiology
Applying Legal Principles to Clinical Practice
Assessing radiological negligence requires more than demonstrating retrospective visibility; it demands careful reconstruction of the original reporting context.
Original study
Review the complete source examination, including protocols, image quality, anatomical coverage, and relevant prior studies.
Clinical context
Establish the referral information and clinical questions available to the original reporter at the time.
Interpretation
Distinguish a perceptual oversight from an abnormality that was detected but reasonably interpreted differently.
Communication
Verify whether urgent or unexpected findings were appropriately escalated, communicated, and logged through proper pathways.
Causation
Determine what a competent report would have changed in terms of follow-up imaging, referral, intervention, and ultimate outcome.
Part IV
NHS and claims data
NHS Resolution
NHS Resolution publishes national data detailing clinical negligence claims, expenditure, and resolution methods. Note that these figures reflect claims activity rather than the absolute incidence of clinical error.
Annual Report
In 2025/26, NHS Resolution received 15,236 new clinical negligence claims and reported incidents. Eighty-four per cent of claims were resolved without formal proceedings.
Interpretion
While these figures reflect rising claim volumes and a continued focus on maternity safety, this record 84% early resolution rate was driven by the first-year success of the "Resolution Through Collaboration" strategy. By prioritizing early settlements, rolling out the CaseHub digital transformation, and partnering with the NAO and PAC, NHS Resolution successfully minimized the emotional and financial burden of litigation while turning claims data into actionable patient safety insights.
Source: NHS Resolution, Annual Report and Accounts 2025/26.
Incidental Findings in Abdominal Radiology Claims
A retrospective review by five abdominal-radiology expert witnesses examined 112 medicolegal cases comprising 176 individual examinations.
Findings
- Forty-one of 112 allegations (37%) involved incidental pathology.
- Suspected malignancy represented the most frequent incidental finding allegation.
- Twelve of the 41 incidental interpretations were judged substandard.
Limitations
This analysis represents a selected expert-witness cohort rather than a national dataset.
Source: Halligan S, Blunt D, Boone D, Higginson T, and Plumb AA, Clinical Radiology, 2026;92:107162.
Part V
Expert evidence
A Defensible Expert Approach
Medical experts owe an overriding duty to assist the court rather than the instructing party. Opinions must clearly distinguish retrospective visibility from prospective standards of care, and critically assess whether a competent report would have altered the clinical outcome.
Breach
- Examine original source images where available.
- Record technical parameters, image quality, and study limitations.
- Define precisely what information was available to the original reporter.
- Review prior imaging in strict chronological sequence.
- Assess objectively whether the report fell outside responsible practice.
Causation
- State what a competent report should have contained.
- Identify the probable clinical response to that report.
- Isolate radiological opinions from other specialist medical evidence.
- Avoid assuming an earlier diagnosis guaranteed an improved clinical outcome.