What is the Mental Capacity Act 2005?

05th December 2025

Updated: Friday 3rd April 2026

What’s the Mental Capacity Act?

So, What is the Mental Capacity Act 2005? The Mental Capacity Act 2005 dictates how decisions are made on behalf of adults in England and Wales, aged 16 or over, who lack the capacity to make some or all decisions for themselves.

This is what happens under the Act:

• People must be assumed to have capacity, so the onus is on clearly showing they lack it.
• Support should always be given for people to make their own decisions, whenever possible.
• Just because someone makes an unwise decision, it doesn’t necessarily mean they lack capacity.
• Any decision made for that person absolutely must be in their best interests and try to not restrict any of their freedoms.

The MCA applies to decisions about everyday life, like what to eat or where to live, as well as more serious decisions like those about medical treatment, care, finances or personal welfare.

What does the Care Act 2014 do?

The Care Act 2014 lays out responsibilities for care and support when it comes to local councils. It outlines how care needs are assessed, who qualifies for that care and what support carers are entitled to deliver the care. All this means that:

• Local authorities are compelled to promote an individual’s wellbeing when assessing care or support needs.
• Thankfully, carers (family or friends) now have legal rights to assessment and support, in addition to the person needing care.
• There is a national eligibility criteria to ensure consistency across adult social-care assessments.

The Act also addresses safeguarding for vulnerable adults and the general quality of care. 

So how do the MCA and Care Act work together?

When a person lacks capacity to make decisions, the MCA provides the legal test and principles for how to make a judgement call on their decision-making. The Care Act ensures local authorities assess a person’s care needs and provide the necessary support, including taking into account when capacity issues arise. They work in tandem to ensure:

• Decisions about care and support are always made in the person’s best interests, with their mental capacity assessed properly as part of that.
• Carers and family members also have rights to support and assessment, not just the primary person needing care.
• Safeguarding and welfare are a primary consideration when people lose capacity or need long-term support.

For example: if someone with dementia needs a care plan, the council will assess their needs under Care Act rules, but the actual decision about care will likely be guided by the MCA framework.

Who is protected by all this and who makes decisions when capacity is lost?

If a person lacks the mental capacity to make decisions, decisions can be made using the MCA by:

• The attorney appointed under an LPA
• If an LPA isn’t in place, a legal deputy appointed by the Court of Protection.

When a care plan is arranged under the Care Act, decisions about consent and treatment must comply with the all the principles of the MCA in order to keep the person’s autonomy central to how it’s used.

What should I bear in mind when using an LPA with either of these Acts?

An LPA can ensure compliance with both the MCA and Care Act if:

• You lose your mental capacity through dementia, illness or injury
• You want to ensure clear, legal authority over your care, medical treatment, property or finances if you’re no longer able to make decisions
• You want to make sure your wishes and values are respected, even if you couldn’t voice them yourself in the future
• You want to avoid the delays and costs of a Court of Protection application, when you haven’t registered an LPA early enough

These Act’s work together to create a powerful protective system for vulnerable adults that balances their rights, autonomy and care.

Applying, through a service like Power of Attorney Online, to register an LPA is the best way to make life easier for those who could end up caring for you in the future.