Hiding Behind the First Principle

Have you ever suspected a client or patient might lack capacity, only to be told no action could be taken because “we must assume they have capacity”? 

This article explores how the first principle of the Mental Capacity Act 2005 (MCA) – the presumption of capacity – is sometimes misunderstood, misapplied, and even used as an excuse for inaction. 

What is the First Principle? 

The MCA (s.1(2)) states: “A person must be assumed to have capacity unless it is established that he lacks capacity.” 

This presumption exists to protect our basic right to make decisions if we are able. Imagine walking into a doctor’s office and being told you lacked capacity before you had even spoken – this is exactly what the principle seeks to avoid. 

However, in practice, it is sometimes misused. Instead of being a safeguard for autonomy, it can become a convenient shield: “we don’t need to assess, because we must assume capacity.” 

The Problem in Practice 

During one assessment, I visited an elderly gentleman in a care home. He had a diagnosis of dementia, could retain new information for no more than 10 minutes, and required support with every aspect of daily living. Yet when I checked his file, there were no mental capacity assessments recorded. 

The explanation? “There’s no need – we must assume capacity.” 

This is where the principle goes wrong. The presumption of capacity is not a reason to avoid assessing when there is good cause for concern. In fact, when clear red flags appear – confusion, severe memory impairment, self-neglect, or decisions with serious consequences – we have a duty to investigate further. 

What the Law Tells Us 

Courts and policy bodies have made clear that the presumption of capacity should not be misapplied: 

• Royal Bank of Scotland Plc v AB (2020): The judge determined that when there is good cause for concern that a person may lack capacity, the presumption cannot be used to avoid taking responsibility for assessing and determining capacity. In this case, the tribunal erred by failing to order an assessment despite obvious concerns. 

• House of Lords Post-Legislative Scrutiny Report (2014): The committee warned of a “worrying tendency” for authorities to invoke the presumption as a reason to “do nothing”, particularly in cases of self-neglect. 

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These emphasise that the presumption of capacity is not absolute. Where doubt exists, we have to go further and a structured assessment of capacity is required. 

After nearly twenty years of the MCA, it is easy to assume its principles are well understood. Sadly, they are still too often misapplied. 

The presumption of capacity remains fundamental – but it is not a free pass to ignore concerns. As the courts and parliamentary committees have made clear, we cannot hide behind it as an excuse to do nothing. 

The real challenge is how do we strike the right balance: respecting autonomy whilst ensuring that when capacity is in doubt, it is properly assessed. 

As professionals, we must constantly be asking ourselves - are we truly respecting capacity, or are we avoiding responsibility?