Mental Capacity Assessment ; what are the five principles of the Mental Capacity Act?

The Mental Capacity Act 2005 sets out five ‘statutory principles’:

The five key principles are:

Principle 1 – A presumption of capacity.
Principle 2 – The right to be supported when making decisions.
Principle 3 – An unwise decision cannot be seen as a wrong decision.
Principle 4 – Best interests must be at the heart of all decision making.
Principle 5 – Any intervention must be with the least restriction possible.

Close up of people's hands and notebooks on a table, conducting mental capacity assessments

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With a range of different specialities, the Mental Capacity Assessment team can conduct a variety of capacity assessments and lasting power of attorney. 

The team are available for instruction throughout the UK.


Principle 1

A presumption of capacity

Every adult has the right to make their own decisions and they must be assumed to have the mental capacity to make decisions, unless an assessment deems otherwise. Health professionals cannot assume that an adult cannot make a decision for themselves if they have a particular illness or disability, mental or physical.

Furthermore, in relation to this Principle, an assessment must only be sought if there is evidence to suggest that capacity might be an issue in terms of the decision that is being made.

Principle 2

The right to be supported when making decisions

All adults must be given every opportunity with support and information before it can be decided that they cannot make decisions for themselves. Every effort to encourage and support people to make decisions for themselves must be given, for example giving information in an alternative format to make it easier to understand – this is often referred to as ‘maximizing capacity’.

Principle 3

An unwise decision cannot be seen as a wrong decision

The individual must keep the right to make decisions, which others may deem as unwise. Such a decision must not be used as a reason to establish lack of capacity, as each person has their own preferences and beliefs, these may be in complete contrast to those who would otherwise determine them as lacking in capacity.

Principle 3 enables a person’s culture and individual characteristics to be taken into account when they are making decisions and it is clear that any decision that an individual makes, where they have capacity to do so, must be respected no matter how odd it may seem.

The Principle also enables health and social care professionals to consider if the individual has capacity but also to determine if the individual is under pressure from someone else to make a decision. For example, if an individual suddenly decided to change their will and leave all of their money to a person they almost never see but who has recently been to visit them, there may be cause for concern that the individual has been coerced into the decision.

However, it must be taken into account that when an individual repeatedly makes unwise decisions which leave them at significant risk or when they make a decision that is out of character, this should warrant further investigation.

Principle 4

Best interests must be at the heart of all decision making

Decisions can only be made on behalf of an individual once it has been completely established that they lack capacity.

Any decision made on behalf of individuals who lack capacity must be done in their best interests. This means that what they would decide, if they had the capacity to do so should be the basis of the decision that is made. This can be very complex and depends on many factors that will maintain the individual’s wellbeing in a holistic manner, which means that all of their needs are taken into account.

It must also take into account the individual’s past wishes or actions, which includes an form of advance statement or directive that has been put into place.

Principle 5

Any intervention must be with the least restriction possible

Any decision made on behalf of individuals who lack capacity must be done in a manner which is least restrictive to their freedom and their basic rights. Any intervention should be assessed given the circumstances of that particular case.

The decision make must, according to this Principle, consider all options available to them and always consider if there is a less restrictive option to the one proposed.

Sometimes, it is determined that what is in an individual’s best interests is not necessarily that which is the least restrictive. In such instances, consideration must be given to amendment to forms of care and support which are less restrictive but which do not put the individual at risk and which still ensure that their needs are met.

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Posted on December 7th 2021

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