The Mental Capacity Act (England and Wales)
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  • Came into force in 2007
  • Applies to everyone over 16 in the UK
  • Provides the legal framework to make decisions for those who lack capacity to do so themselves
  • Protects people who lack capacity
  • Empowers individuals who may have reduced capacity to still make decisions for themselves
The act also allows people to make decisions about their future health treatment in the event that their mental capacity may be reduced – ADVANCED DIRECTIVES (aka living wills). These are essentially used to make advanced decisions to refuse treatment.
  • you can also make a ‘written statement’, that can be used in the future to decide what should be in your best interests, and who should be involved in the decision making process
  • you are also allowed to appoint a lasting power of Attorney – this means you appoint an individual whom you will allow to make decisions on your behalf in the future if you became unable to make them yourself.

Key Principles in the decision making process

  • The act is there to provide support to those who may not have capacity to make decisions
  • everyone is assumed to have mental capacity unless proven otherwise
  • in practical terms, this might mean that some people who may be perceived as having reduced capacity do infact have normal capacity, providing they are given enough time, support and information to make the decision. The act aims to provide these additional resources to such people.
  • just because you disagree with a decision, or it seems illogical, does not mean that the person making the decision lacks capacity.
  • Lacking capacity for one particular decision (e.g. type of treatment) does not mean you lack capacity for all decisions
  • Lacking capacity at a particular time, does not mean you lack capacity in the future. Each decision has to be individually assessed.
  • Someone making a decision for you should still involve you as much as possible in the process
  • All actions carried out under the act are done in the best interests of the individual involved, and limit as much as possible restrictions on basic rights and freedoms

The act introduced

  • new laws making it illegal to willfully neglect someone who lacks capacity
  • a service called the Independent Mental Capacity Advocacy Service who help make decisions for people who have no close relatives involved in the decision making process. Usually an independent Mental Capacity Advocate is appointed to an individual to help them make decisions.
  • a court of Protection – that can make the final decision on capacity if necessary. It can also appoint someone to make these decisions in the future.
  • The Office of the Public Guardian – provides advice to the general public about the Act, and also is involved with Power of Attorney applications
  • New protections for patients who lack capacity but whom may be involved in research. Essentially an ethics committee has to agree that the research:
    • Is safe
    • Is relevant to the patient condition
    • Cannot be carried effectively out on those with normal mental capacity
    • Must produce overall benefit to the individual
    • Carers and family members also have to consent

Practical use of the act

People may have capacity to make some decisions, but not others (e.g. what to have for tea, but not to decide what treatment they will have). You can asses mental capacity with 4 main criteria:
  • Is the patient able to understand verbal and/or written information needed to make the decision?
  • Are they able to retain this information long enough to make the decision?
  • Are they able to weight up the pro’s and con’s of a decision?
  • Are they able to communicate their decision?

Who assesses capacity?

For everyday decisions – it is likely to be a relative, friend or carer
For medical decisions – it is likely to be a medical professional
For legal decisions – it is likely to be a solicitor

What happens if the person is judged to lack capacity?

Then someone else will make the decision for you, but they have to involve you as much as possible in the process. There are some decisions which cannot be made for an individual, despite lack of capacity. These include decisions about:
  • Voting
  • Marriage / divorce / relationships
  • Detainment and treatment against the patient’s will – these are separate, and are covered by the Mental Health Act


Under the act, you can only physically restrain somebody who lack capacity against their will if doing so will prevent harm to the patient. You are only allowed to use reasonable, proportional force.

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) currently works as a GP Registrar and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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