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It is a general legal and ethical principle that valid consent must be obtained before starting treatment or physical investigation or providing personal care for a person.

This principle reflects the right of patients to determine what happens to their own bodies, and is a fundamental part of good practice.

A healthcare professional (or other healthcare staff) who does not respect this principle may be liable both to legal action by the patient and to action by their professional body.

If healthcare professionals (or other healthcare staff) fail to obtain proper consent and the patient subsequently suffers harm as a result of treatment, this may be a factor in a claim of negligence against the healthcare professional involved.

Poor handling of the consent process may also result in complaints from patients through the NHS complaints procedure or to professional bodies.

What is Consent?

In order for there to be an effective consent to treatment, it is not enough to show that the patient said “yes”. There must be genuine
agreement to receive the treatment. It is necessary to show that:

  • The patient is competent
  • The patient is sufficiently informed &
  • The patient is not subject to coercion or undue influence

Chester vs. Afshar

This case involved a patient with lumbar disc protrusion who was operated on electively 3 days after initial consultation by the surgeon.

The patient ultimately ended up with cauda equina syndrome and proceeded to sue the surgeon on grounds of negligence.

Cauda equina syndrome was considered as a recognised risk of the surgery but the patient was not informed of this risk pre-operatively. The patient admitted that, having known of this, she would still have undergone surgery. However, she claimed that she would have sought a second opinion had she had more time to do so. After an involved legal process, the award of compensation to the patient was finally ordered in the House of Lords.

In a majority judgment (3:2), it was held that patients should be told of any possible serious risks associated with their proposed medical treatment.

Crucially, the Law Lords ruled that to succeed in a claim for negligence, the patient did not have to prove that they would have rejected the treatment that had been inadequately explained to them, only that they might have sought further advice or time to reflect further before making a decision.

The judge held that the operation was not negligently performed but that Mr Afshar was negligent in not properly informing Ms Chester of the risks. Had he done so, she would have sought second or even third opinions and would not have had the surgery when she did. Therefore, he was responsible for her injuries.

The House of Lords concluded that, though the failure to warn was not a direct cause of injury, it did result in negligence.

Chester vs Afshar Consequences

General Medical Council. In the wake of this judgment, the General Medical Council issued revised guidance. It emphasises the duty of doctors to act in partnership with their patients with respect to obtaining their consent to medical treatment.

Doctors are advised to disclose risks arising from treatment that may result in common but minor side effects, as well as rare but serious adverse outcomes that may result in permanent disability or death. The guidance specifically states that where risks are beyond the minor or routine, the patient’s written consent should be obtained.

NHS Litigation Authority 2004.


  • Extreme care in the taking of consent is even more crucial than ever.
  • Careful & comprehensible warnings about all significant possible adverse outcomes must be given.
  • These warnings must be properly recorded in the notes.
  • The patient should be invited to sign the relevant entry to confirm that he / she has been given the warnings, has understood it and accepts the risk.
  • It is equally important to make a full entry in the notes, preferably signed by the claimant, if treatment is refused, including the reason when given.
  • Whenever possible, the clinician who discussed and is able to perform the treatment should be the one who obtains the consent.

Hempsons Solicitors 2005.

The advice after Chester was that surgeons should carefully record in the patient’s notes the risks of which they have warned the patient and ask the patient to sign that record. The implication of Chester applying to other medical treatment is that all doctors might have to follow this advice when prescribing any drug with potentially serious side effects …and this in itself would be a serious side effect of Chester.

Medical Protection Society 2008.

The Chester case established on policy grounds that the patient’s autonomy and dignity required that she be allowed the time to make an informed decision. So, in the wake of Chester v Afshar, it is imperative that care is taken to warn patients about all risks material to their decision and, when time permits, that they are encouraged to consider their options over time before deciding whether or not to undergo treatment.

Department of Health, Reference guide to consent for examination or treatment. 2nd Edition. 2009.

Chester v Afshar. The House of Lords judgment held that a failure to warn a patient of a risk of injury inherent in surgery, however small the probability of the risk occurring, denies the patient the chance to make a fully informed decision. The judgment held that it is advisable that health practitioners give information about all significant possible adverse outcomes and make a record of the information given.

This is the Consent Form that has been introduced by Dartford & Gravesend NHS Trust (something similar has been introduced at the St Peters & Ashford Hospitals; it is likely other NHS Trusts have done so however I have not, as yet, come across them). The Chester vs Afshar case is mentioned (highlighted in green) however there is minimal space to list the various warnings as demanded by the ruling of the Chester vs Afshar case!

In Practice

Chester vs Afshar boils down to 2 principles:

  1. All risks (no matter how small) and information must be given to the patient.
  2. The patient has to have time to digest and think on the information given regarding the risks attendant on the operation.

Thus, information has to be provided and this can be in the form of information sheets, websites, DVD’s etc.

Enough time to digest and think through the information means that the patient is not given all this information just prior to the procedure. This is inappropriate as:

  1. There is a lack of time to permit a considered decision
  2. It is in an inappropriate environment for sympathetic and considerate discussion
  3. There is a perceived lack of any alternative to acquiescence on the part of the patient.
  4. There is a placing of a definitive decision at the culmination of a preparation process rather than closer to the outset

The confirmation of consent is best obtained outside of the procedure room and would be reflective of an ethos of good patient centred practice with regard for timeliness and unpressured decision making.

Also, “If a person is not asked to signify their consent until just before the procedure is due to start, at a time when they may be feeling particularly vulnerable, there may be real doubt as to its validity.” DOH Model Policy