Medical negligence claims rest on four legal foundations. If you cannot establish all four, the claim will not succeed. This guide explains what each one requires and what evidence is needed to support it.

Nothing here is legal advice. If you believe you have a claim, speaking with a regulated solicitor early gives you the best chance of preserving the evidence you will need.

What counts as medical negligence?

Medical negligence is not the same as a bad outcome. It is a legal wrong: a healthcare professional owed you a duty of care, fell below the standard a competent professional would have met, and that failure caused you harm you would not otherwise have suffered.

A surgeon who carries out a technically difficult procedure correctly but whose patient still deteriorates has not been negligent. A surgeon who operates on the wrong site has. The question is always about the standard of the care delivered, not the outcome alone.

The four elements you must establish

Every medical negligence claim in England and Wales requires proof of all four of the following:

  1. Duty of care. The healthcare professional or NHS trust owed you a duty. This is almost always straightforward once a clinical relationship exists. A GP who accepts you as a patient owes you a duty. A hospital that treats you in A&E owes you a duty.

  2. Breach of duty. The standard of care fell below what a reasonably competent practitioner in that specialty would have provided. This is assessed against the Bolam test (see below).

  3. Causation. The breach caused your harm. This is legally separate from breach and is often the most contested element in a claim.

  4. Damage. You suffered quantifiable harm as a result: physical injury, psychiatric injury, financial loss, or a combination.

Proving three out of four is not enough. A claim that fails on causation fails entirely, even if the breach is clear.

What is the Bolam test?

The Bolam test is the legal standard used to assess whether a medical professional breached their duty of care. It comes from Bolam v Friern Hospital Management Committee [1957], in which the court held that a doctor is not negligent if they act in accordance with a practice accepted as proper by a responsible body of medical opinion in that specialty, even if other doctors would have done something different.

This means a claimant cannot win simply by finding one expert who disagrees with the treatment given. The defendant's approach must fall outside a range of practice that no responsible body of professionals would have endorsed.

The Bolam test was refined in Bolitho v City and Hackney Health Authority [1997]. The House of Lords held that a responsible body of medical opinion must also be capable of withstanding logical analysis. A court is not bound to accept expert evidence just because a group of doctors endorses it. If the expert opinion is illogical or fails to account for obvious risks, the court can reject it.

In practice, Bolitho is rarely decisive on its own, but it prevents defendants from shielding genuinely poor practice behind expert consensus.

How does the consent standard work?

Consent is governed by a separate and more demanding standard since Montgomery v Lanarkshire Health Board [2015], in which the Supreme Court moved away from Bolam for consent issues entirely.

Under Montgomery, a doctor must warn a patient of any material risk involved in a proposed treatment. A risk is material if a reasonable person in the patient's position would attach significance to it, or if the doctor knows (or should know) that this particular patient would.

This matters for claims involving inadequate consent. If you were not told of a risk that later materialised, the question is not whether other doctors would have disclosed it, but whether a reasonable patient would have wanted to know. That is a lower bar for claimants and a higher bar for defendants.

How causation is proved

Establishing causation requires showing that, but for the negligent act or omission, you would not have suffered the harm you did. This is called the "but for" test, derived from Barnett v Chelsea and Kensington Hospital [1969]. In Barnett, a patient attended A&E and was sent home negligently. He later died of arsenic poisoning. The claim failed on causation: he would have died even with correct treatment, so the negligence did not cause his death.

Causation failures are more common than people expect. A GP who failed to refer a patient for cancer screening may have been clearly in breach, but if the cancer was already at a stage where earlier detection would not have changed the outcome, the claim cannot succeed.

Two scenarios where causation becomes particularly complex:

  • Loss of chance cases. Some claims argue that negligence reduced the claimant's chance of recovery. English courts have generally not allowed damages for loss of chance in personal injury cases, though this area of law continues to develop.
  • Multiple causes. Where a claimant's condition has several potential causes, establishing that the defendant's negligence was the material cause (rather than one of many contributing factors) requires detailed expert analysis.

Both scenarios require specialist medical expert evidence. Your solicitor will commission this; it is not something you can gather yourself.

What evidence do you need?

Three categories of evidence form the foundation of every medical negligence claim:

1. Your medical records. You have a right to access your medical records under the Data Protection Act 2018 and UK GDPR. Records from your GP, hospital, and any specialist are all relevant. Your solicitor will obtain these on your behalf, but you can also request them directly from your GP or the hospital's Subject Access Request team.

Obtaining records as early as possible matters. The quality of clinical notes, correspondence between clinicians, and imaging reports all become harder to reconstruct as time passes.

2. An independent medical expert report. This is the non-negotiable element of any claim. No expert report, no claim. The expert must be a practising clinician in the same specialty as the defendant and must address both breach of duty and causation in a written report.

3. Witness evidence. Your own account of events, and where relevant the accounts of family members who were present, can support the claim. Witness evidence alone cannot establish breach or causation, but it provides important factual context and can be decisive on issues of consent.

What is a medical expert report and why is it essential?

An independent medical expert report addresses the two central questions in your claim: whether the standard of care fell below what was expected, and whether that failure caused your harm.

The expert must be currently practising (or recently retired) in the relevant specialty. An orthopaedic surgeon cannot opine on GP negligence. A general practitioner cannot opine on surgical technique. Courts and defendants scrutinise expert qualifications closely, and an expert who strays outside their specialism will carry little weight.

Most solicitors instruct expert witnesses they have used before and whose reports withstand cross-examination. This is one of the practical reasons why specialist solicitor instruction at the outset significantly affects the strength of a claim.

Can you prove medical negligence without a solicitor?

Technically, you can bring a claim as a litigant in person. In practice, it is very difficult. NHS Resolution (the body that defends NHS trusts) employs specialist clinical negligence solicitors and medical experts. Their legal teams are experienced in contesting liability and quantum at every stage.

Without a solicitor, you would need to commission your own expert evidence, understand pre-action protocol obligations, draft a Letter of Claim, analyse the Letter of Response, and if the claim does not settle, navigate High Court or County Court litigation. The procedural complexity alone defeats most unrepresented claimants before the merits are ever tested.

Under a CFA arrangement (Conditional Fee Agreement), you pay nothing upfront and nothing if the claim is unsuccessful. If it succeeds, a success fee of up to 25% of your past losses and general damages is deducted, as set by the CFA Order 2013. Future losses are fully protected and cannot be touched.

How long do you have to prove a medical negligence claim?

Under the Limitation Act 1980, you have three years to bring a medical negligence claim in England and Wales. This runs from either:

  • The date of the negligent act, or
  • The date of knowledge: the date you first knew, or could reasonably have known, that the treatment you received may have caused your harm.

The date of knowledge exception is important. If your harm only became apparent years after the negligent act, the three-year clock starts when you first had reason to suspect a link, not when the treatment took place.

Three further exceptions:

  • Children. The limitation period does not start until the child turns 18. A parent or guardian can bring a claim on their behalf before then.
  • Adults lacking mental capacity. The limitation period does not run while the person lacks capacity.
  • Deaths. Three years from the date of death, or from the date the personal representative first had knowledge that negligence may have caused the death.

Even where the limitation period has not expired, acting early is consistently better. Evidence is easier to gather, medical records are more complete, and expert witnesses can provide clearer opinions when events are more recent.

How AAA Solicitors can help

AAA Solicitors handles all categories of medical negligence claim in England and Wales, including high-value and complex cases involving birth injury, surgical error, delayed diagnosis, and GP failures. All claims are funded under a Conditional Fee Agreement: nothing is payable upfront.

The first step is a free initial assessment. You can start that process now by completing the form on this site or calling us directly. An initial conversation commits you to nothing and costs you nothing.

If you want to understand each claim stage from the first call to settlement, the claims process guide covers every step.