The Mental Capacity Act 2005 (MCA) is the law in England and Wales that protects and supports people who may have difficulty making certain decisions for themselves. It applies to everyone aged 16 and over and covers decisions about health, care, finances and every day life. 

At its heart, the Mental Capacity Act is about respecting autonomy while ensuring people are properly supported and safeguarded.

They key principles of the Mental Capacity Act

The Act is built on five important principles:

1. Everyone is assumed to have capacity. A person must be assumed to be able to make their own decisions unless it is shown otherwise.

2. All practical help must be given first. A person should be supported to make their own decisions wherever possible, for example by using simple language, visual aids, or being given more time to consider.

3. People can make unwise decisions. Making a decision others disagree with does not mean someone lacks capacity. 

4. Decisions made for someone must be in their best interest. If a person cannot make a decision themselves, any decision made on their behalf must prioritise what is best for them, not what is easiest or most convenient.

5. Use the least restrictive option. Any decision or action taken should interfere as little as possible with a person's rights and freedoms.

How the MCA principles are applied in reality. Let's explain in a clear way, rather than talk about abstract legal principles.

A hospital discharge scenario where Mrs A is an 82-uear-old woman who has been admitted to hospital falling a fall. Medically, she is now fit for discharge. She lives alone and has mild cognitive impairment.

The hospital social worker is concerned about whether Mrs A will be safe is she returns home without support. Mrs A, however, is very clear: she wants to go home.

There is where the MCA 2005 becomes crucial.

Step 1: Presume capacity

Under the MCA, Mrs A must be presumed to have capacity unless it is established otherwise. Concerns about risk or vulnerability do not automatically mean she lacks capacity. The question is not "Is this a risky decision?", but instead, "Does Mrs A have the capacity to make this decision?"

Step 2: Support the person to make the decision

Before any formal capacity assessment is undertaken, professionals must take all practicable steps to support Mrs A to decide for herself. This might include:

• Explaining the risks and options in simple language
• Breaking information down into manageable parts
• Allowing time for discussion
• Involving a trusted family member or advocate (with Mrs A's consent)

Only if these steps fail can incapacity be considered.

Step 3: Capacity is decision-specific

Capacity is assessed in relation to the specific decision at hand, here, the decision is about discharge and returning home. Mrs A may lack capacity to manage complex finances, but still have capacity to decide:

• Where she wants to live
• Whether she accepts support at home

The capacity assessment focuses on whether she can:

• Understand the relevant information
• Retain it long enough to decide
• Use or weigh that information
• Communicate her decision