Mental Capacity Act 2005 in Care Settings: Capacity Assessments, Best Interests and Legal Responsibilities

2nd March 2026

Written by Stephanie Austin, Owner & Lead Trainer at Prima Cura Training
Reviewed: February 2026. Next Review Due: February 2027 (or sooner if legislation, regulations, or guidelines change)

What is the Mental Capacity Act 2005?

The Mental Capacity Act 2005 is UK legislation that protects people who may lack the capacity to make specific decisions. It sets out a two-stage test for capacity and five key principles that must guide lawful decision-making in health and social care.

There are certain moments in care and support work that stand out as distinct. You know them when you’re in them.

The conversation slows slightly. The stakes feel higher, and people choose their words more carefully. There is a sense, even if nobody names it, that whatever happens next matters in a way that goes beyond routine.

It might be when someone refuses clinically important medication. Perhaps when an individual insists on going out alone late at night and staff feel uneasy about what could happen. Or when a daughter says, firmly and emotionally, that her mum would “never want this”. How about when someone suggests locking a door “just to keep things safe”?

In those moments, the Mental Capacity Act 2005 is not theoretical; it is not background policy. It is a legal boundary.

And make no mistake, if you work in care, you hold power.

You hold the power to support. You hold the power to restrict. You hold the power to override. You hold the power to decide when someone cannot.

The MCA exists to make sure that power is exercised lawfully, proportionately, and with respect for human rights, as set out in the Mental Capacity Act 2005 and expanded in the statutory guidance within the Mental Capacity Act Code of Practice.

This is not small legislation. This is serious territory. Decisions under the Mental Capacity Act affect liberty, bodily integrity, accommodation, finances, health treatment, and the very shape of someone’s day-to-day existence. That is why it deserves depth, not summaries.

If at any point while reading this you recognise that your team would benefit from a deeper, scenario-based understanding, that is exactly what our structured Mental Capacity Act 2005 Training Course is designed to support.

Capacity Is Not a Label

Before We Go Any Further, one of the most persistent and quietly dangerous habits in services is the global statement.

“They lack capacity.”

It can sit at the top of a care plan as though it were a permanent trait, like height or eye colour. It can be repeated in handovers until it feels factual, unquestionable, and almost convenient.

But capacity is not a personality feature.

Capacity is:

Decision-specific
Time-specific
Context-specific

This principle is clearly embedded in the legislation itself under Sections 2 and 3 of the Act, which you can revisit.

A person might have the capacity to decide what to eat for lunch, but not to understand the implications of signing a legal agreement. They might lack capacity during an acute infection and regain it once the delirium clears. They might understand better in the morning than they do in the evening.

If you ever see or hear capacity treated as global and fixed, that is your cue to slow down.

Because once capacity becomes a label, autonomy starts to shrink quietly.

The Two-Stage Capacity Test Explained

The Mental Capacity Act gives us a clear structure, and when applied properly, it protects both the individual and the professional.

Stage One: Is there an impairment or disturbance in the functioning of the mind or brain?

This might include, but is not limited to:

Dementia
Brain injury
Stroke
Severe mental illness
Learning disability
Delirium
Neurological illness
Temporary intoxication

If there is no impairment, the Act does not apply. That is important.

Stage Two: Because of that impairment, is the person unable to make this specific decision at this specific time?

You must assess whether they can:

Understand the relevant information
Retain it long enough to make the decision
Use or weigh that information
Communicate their decision

The four-stage functional test is outlined directly in the legislation and further clarified in the Code of Practice, both available at the Mental Capacity Act Code of Practice.

The Act focuses on process, not outcome. If someone understands the risk and still chooses the risky option, that may still be capacity.

And that is often where practice becomes uncomfortable.

The Five Core Principles of the MCA

The five principles in Section 1 of the Act underpin every lawful decision under the MCA.

Let’s sit with them properly.

1. Presume Capacity: Start From Respect, Not Doubt

The law requires you to assume capacity unless it is established otherwise.

This is not optimism. It is a safeguard against unnecessary paternalism.

Imagine a gentleman with early-stage dementia who refuses to attend a GP appointment. It would be easy, particularly under time pressure, to conclude that he does not understand what he is refusing. But the presumption of capacity demands that we test that assumption, not default to it.

Under CQC Regulation 11 – Need for Consent, inspectors expect to see that presumption reflected in practice.

2. Support Decision-Making: If You Haven’t Tried Properly, You Haven’t Assessed Properly

Before deciding someone lacks capacity, you must take all practicable steps to help them decide.

Support might look like:

Choosing a quieter environment
Breaking information into smaller parts
Using visual aids
Checking hearing aids
Allowing more time

The requirement to support decision-making is reinforced within the statutory guidance Mental Capacity Act Code of Practice.

If you skip this stage, any capacity assessment that follows is on shaky ground.

3. Unwise Decisions: Autonomy Includes Risk

A person is not to be treated as lacking capacity merely because they make an unwise decision.

This is clearly stated within Section 1 of the Act.

Autonomy does not require professional agreement; it requires deep understanding and the application of person-centred care.

4. Best Interests: Structured, Transparent, Lawful

When someone genuinely lacks the capacity for a specific decision, any action taken must be in their best interests.

The best interests checklist is outlined in Section 4 of the Act and expanded in the Mental Capacity Act Code of Practice.

You must consider:

Past wishes and feelings
Present wishes
Beliefs and values
Cultural and religious context
Views of relevant others
All possible options
Whether the decision can wait
The least restrictive alternative

If your best interests documentation reads like “This is safer,” you have not gone deep enough.

Structured reasoning is your protection (defensible decision making), and it is required to uphold the individual’s rights.

5. Least Restrictive Option: Freedom Is the Default

Even when acting in ‘best interests’, you must consider whether the aim can be achieved in a way that is less restrictive of rights and freedoms.

Restrictions might include:

Locked doors
Constant supervision
Removing access to money
Limiting social contact

If someone lacks capacity and is under continuous supervision and not free to leave, you may be looking at deprivation of liberty requiring authorisation under DoLS.

The legal test for deprivation of liberty was clarified by the Supreme Court in Cheshire West and Chester Council v P (2014). The Court confirmed that a person is deprived of their liberty if they are under continuous supervision and control and are not free to leave, regardless of whether the placement appears comfortable or benevolent. This is often referred to as the “acid test”. The purpose or perceived kindness of the arrangement does not remove the need for lawful authorisation.

A Note on Liberty Protection Safeguards (LPS)

The Deprivation of Liberty Safeguards (DoLS) framework is due to be replaced by the Liberty Protection Safeguards (LPS) under amendments to the Mental Capacity Act 2005. Although implementation has been delayed, LPS will extend safeguards to a wider group of people aged 16 and over and apply across health, social care and certain community settings.

Services should remain alert to updates from the Department of Health and Social Care, as the shift to LPS will change how deprivation of liberty is authorised and reviewed. Until LPS is formally implemented, DoLS remains the current legal framework in England and Wales.

CQC guidance on this area can be revisited at CQC Guidance – Mental Capacity and Deprivation of Liberty.

This is not just paperwork or another administrative focus; it is fundamental human rights law.

The Emotional Weight of Getting This Right

Applying the Mental Capacity Act properly is not just intellectual work; it is emotional work. It requires you to tolerate discomfort and to allow individuals to make choices that worry you.

It requires you to say no to family members who are certain they know best, unless they hold lawful authority such as a Health & Welfare LPA, details of which are outlined in the Lasting Power of Attorney government guidance.

It requires you to challenge colleagues when assumptions are made too quickly.

This is not easy work, but it is meaningful work. And when you apply it properly, you are protecting something fundamental: a person’s right to remain an adult, even when they need support.

Governance, Inspection and Culture

Under Regulation 11, providers must ensure that care and treatment are delivered with consent or in accordance with the MCA.

MCA, Regulation 11 and CQC Expectations

Under Regulation 11 of the Health and Social Care Act 2008 (Regulated Activities) Regulations 2014, providers must demonstrate that care and treatment are delivered with valid consent or in accordance with the Mental Capacity Act. Where a deprivation of liberty is identified, appropriate legal authorisation must be in place. Inspectors will expect to see a clear link between capacity assessments, best interests decision-making and any DoLS applications.

Inspectors will look for:

Decision-specific capacity assessments
Clear best interests reasoning
Evidence of support attempts
Identification of restrictive practice
Appropriate DoLS applications
Leadership oversight

Strong services embed MCA into culture. They audit it, they reflect on it, and they train for it.

Frequently Asked Questions About the Mental Capacity Act 2005

There are always questions that don’t quite make it into formal policy documents. They tend to come up in corridor conversations, in supervision, or at the end of training when someone says, “Can I just check something…” Let’s answer those properly.

“Does having dementia automatically mean someone lacks capacity?”

No. And this is one of the most important misconceptions to challenge early.

Dementia is an impairment of the mind or brain, which means the Mental Capacity Act framework applies, but it does not mean the person automatically lacks capacity for every decision. Capacity is always decision-specific and time-specific.

Someone with dementia may:

Be able to decide what they want to wear
Be able to decide who they want to see
Be able to decide whether they want a shower right now
Not be able to understand a complex medical consent form

If capacity is assumed to be absent purely because of a diagnosis, that is an unlawful practice.

“What if they make a decision that puts them at risk?”

This is where people often feel the most tension.

The law allows adults with capacity to make decisions that carry risk. That includes decisions you would not make yourself.

The key question is not, “Is this risky?”

The key question is, “Do they understand the risk, can they weigh it, and are they making this decision freely?”

If the answer is yes, then the role of the service shifts from control to support. That might include:

Risk reduction strategies.
Clear documentation.
Open communication.
Safeguarding checks if coercion is suspected.

Risk does not automatically equal incapacity.

And this is where professional maturity really matters.

“Can family members make decisions if someone lacks capacity?”

Not automatically.

Family members do not have decision-making authority simply by being related.

The only circumstances where a family member can lawfully make certain decisions are if they hold:

A valid Health and Welfare Lasting Power of Attorney, or
A Court of Protection Deputyship through an appropriate authority

If there is no LPA or deputy, professionals making the decision must follow the best interests framework properly, consulting the family but not deferring decision-making to them by default.

Love and legal authority are not the same thing.

“What if staff disagree about someone’s capacity?”

Disagreement does not invalidate the framework; it simply means the framework needs to be applied carefully.

If there is disagreement:

Revisit the two-stage test
Check what support was offered
Ensure the decision being assessed is clearly defined
Consider whether a second opinion is appropriate
Document reasoning clearly

Capacity assessments should not be based on hierarchy or personality strength. They should be based on evidence. If necessary, escalation pathways should be clear within your governance structure.

“What happens if there is a dispute about best interests?”

Sometimes disagreements cannot be resolved internally, particularly around major decisions such as accommodation or serious medical treatment.

In those cases, the matter may need to be referred to the Court of Protection.

This is not a failure of the service. It is part of the lawful structure that exists to protect individuals when decisions are complex or contested.

The important thing is that the best interests reasoning up to that point has been thorough, transparent and documented.

“Can someone regain capacity?”

Yes. Capacity can fluctuate.

Someone experiencing delirium due to infection may lack capacity today and regain it next week. Someone experiencing acute mental health distress may have reduced decision-making ability temporarily.

That is why review dates matter.

Capacity assessments are not one-off declarations. They should be revisited where circumstances change.

“What if someone refuses care that keeps them safe?”

This is one of the hardest practical situations. If the person has capacity, they are entitled to refuse care, even if that refusal carries risk.

If they lack capacity, you move into best interests decision-making. But what you cannot do is override capacitous refusal simply because it makes staff uncomfortable or increases workload.

That is where the line between protection and control becomes very real.

“Is documentation really that important?”

Yes. Completely.

If a decision is ever scrutinised by CQC, safeguarding, a complaint, or in extreme cases, legal proceedings, documentation is what demonstrates your reasoning.

Clear records should show:

What the decision was
Why capacity was in question
What support was offered
The outcome of the assessment
Best interests reasoning
Why the chosen option the least restrictive

If that structure is missing, it becomes very difficult to evidence lawful practice.

“Why does this feel so complicated in real life?”

Because it is. The MCA sits at the intersection of safety, autonomy, emotion, family dynamics, risk, and organisational pressure.

It asks you to balance compassion with restraint. It asks you to tolerate risk. It asks you to slow down when everything around you is busy. And that is not simple. But complexity does not mean impossibility.

It means the framework matters.

“How do we make sure our team gets this right?”

Consistency comes from:

Structured, scenario-led Mental Capacity Act 2005 Training Course
Reflective supervision
Regular audit
Open discussion about restrictive practice
Leadership that genuinely values autonomy

The MCA is not just a legal framework. It is a cultural one.

A Final Word on Why This Matters

The Mental Capacity Act 2005 is not there to make your job harder.

It is there to ensure that when someone is vulnerable, their rights do not quietly shrink in the name of convenience or fear.

It protects the person. And when applied properly, it protects you, too.

Because lawful, thoughtful, structured decision-making is always stronger than assumption.

Disclaimer: This guide is for educational purposes only and does not constitute legal advice. Always refer to the Mental Capacity Act 2005, the MCA Code of Practice, and current statutory guidance when making decisions. Always consult your safeguarding lead or legal advisor where appropriate.

News & Blog