Why the UK Mental Capacity Act 2005 Must Be Repealed or Struck Down: A Human Rights, Constitutional, International Law, and Real-World View

The Mental Capacity Act 2005 (MCA) was intended to protect vulnerable individuals and empower those who may lack capacity to make decisions. In reality, it has become a legislative framework that enables systematic discrimination, paternalism, and serious violations of constitutional and human rights. Far from reflecting modern legal standards, the MCA is fundamentally incompatible with centuries of British constitutional law, international human rights treaties, and evolving common law principles across the Commonwealth.

1. Historic Constitutional Guarantees of Liberty

For centuries, English law has safeguarded the right to liberty and the rule of law:

Magna Carta 1225 & 1297, Clauses 29 and 39, guarantee that no free person shall be “imprisoned or disseised… except by the lawful judgment of his peers or by the law of the land.”

The Habeas Corpus Acts (especially 1679) enshrine the right to challenge unlawful detention before a court.

The Bill of Rights 1689 prohibits “cruel and unusual punishments” and affirms the primacy of due process and liberty.

The MCA’s Deprivation of Liberty Safeguards (DoLS) and substituted decision-making frameworks allow state bodies to detain individuals in care homes, hospitals, and institutions without the kind of prompt judicial oversight or jury trial contemplated by these historic constitutional protections. The Supreme Court’s decision in Cheshire West and Chester Council v P [2014] UKSC 19 exposed how thousands are deprived of liberty under administrative procedures, not genuine judicial process.

2. The Right to Petition and Protection from Reprisal

Under the Petition of Right 1628, every subject has the right to petition the Crown and Parliament and to be heard without fear of punishment. Article 5 of the Bill of Rights 1689 reaffirmed this protection.

Yet, individuals and families who have petitioned or complained about MCA procedures—including through the Court of Protection, to local authorities, or via advocacy—have sometimes faced retaliation, withdrawal of services, or punitive measures, contrary to this constitutional guarantee. This undermines not just individual rights but the integrity of the rule of law itself.

3. International Human Rights Law: Incompatibility with the CRPD and Beyond

The United Nations Convention on the Rights of Persons with Disabilities (CRPD), ratified by the UK in 2009, is clear in Article 12:

“States Parties shall recognize that persons with disabilities enjoy legal capacity on an equal basis with others in all aspects of life.”

The UN Committee on the Rights of Persons with Disabilities (2014 Concluding Observations, UK) held that the MCA violates Article 12 by allowing substituted decision-making based on mental capacity assessments. Article 14 CRPD prohibits deprivation of liberty on the basis of disability—yet DoLS are applied overwhelmingly to disabled people.

These are not symbolic findings. Under Article 26 of the Vienna Convention on the Law of Treaties, treaties are binding, and the UK is internationally obliged to bring its laws into conformity.

Further, the ICCPR (International Covenant on Civil and Political Rights), UDHR (Universal Declaration of Human Rights), and the ECHR (European Convention on Human Rights)—incorporated via the Human Rights Act 1998—protect liberty (Article 9 ICCPR; Article 5 ECHR; Article 3 UDHR) and freedom from inhuman or degrading treatment (Article 7 ICCPR; Article 3 ECHR).

The European Court of Human Rights has repeatedly held (e.g., Stanev v Bulgaria [2012] ECHR 46, DD v Lithuania [2012]) that institutional placements and substituted decision-making regimes can violate Article 5 (liberty) and Article 8 (private life). These principles apply to the UK, as the UK remains a party to the ECHR post-Brexit.

The Court of Justice of the European Union (CJEU), under retained EU law, continues to influence UK courts, especially regarding fundamental rights as general principles of law. Post-Brexit, these decisions remain persuasive and can be binding in certain contexts under the European Union (Withdrawal) Act 2018.

4. Children’s Rights and Family Life

The UN Convention on the Rights of the Child (UNCRC), incorporated in part through the Children Act 1989, demands that children’s best interests be a primary consideration (Article 3 UNCRC), and that their voices be heard (Article 12). MCA processes often fail to respect these principles for young people turning 16–18, creating legal grey areas that undermine rights guaranteed under the UNCRC and domestic family law.

5. UK Case Law and Common Law

British courts have long affirmed the sanctity of liberty and the right to personal autonomy. In R v Secretary of State for the Home Department, ex parte Khawaja [1984] AC 74, the House of Lords reaffirmed the common law’s role in guarding against unlawful detention. In Airedale NHS Trust v Bland [1993] AC 789, the courts acknowledged the gravity of decisions affecting life and autonomy.

Yet, under the MCA, capacity assessments and “best interests” decisions often override clear expressed wishes, without meaningful court oversight, contradicting the principle in Re C (Adult: Refusal of Treatment) [1994] 1 WLR 290 that capacity must be presumed and autonomy respected.

6. Comparative Common Law Jurisdictions

Australian and Canadian courts, sharing the UK’s common law heritage, have moved towards supported decision-making and stronger rights protections. Cases such as Re Eve [1986] 2 SCR 388 (Canada) and PBU & NJE [2018] VSC 564 (Australia) emphasise autonomy, dignity, and proportionality. These persuasive authorities show a growing consensus that capacity law must be rights-based, not paternalistic.

7. International Adjudicatory Bodies

Although the UK has not been subject to an International Court of Justice (ICJ) or Permanent Court of Arbitration (PCA) judgment on the MCA specifically, these bodies, along with the International Criminal Court (ICC) in human rights contexts, consistently affirm the supremacy of international legal obligations over conflicting domestic practice in matters involving fundamental human rights.

Conclusion: Repeal, Not Reform

The Mental Capacity Act 2005 is not merely flawed in practice — it is incompatible with the UK’s constitutional heritage, in breach of multiple binding international treaties, and out of step with modern human rights jurisprudence domestically and abroad.

Parliament must act to repeal the MCA 2005 and replace it with a framework that recognises universal legal capacity, embeds supported decision-making, and guarantees effective judicial oversight and protection against arbitrary detention. If Parliament refuses to act, the the Supreme Court of the United Kingdon, Court of Appeal, devolved courts, or the High Court of England and Wales should do the right thing and either refuse to accept arguments under this discriminatory Act or outright strike it down.

Such a move would not only fulfil the UK’s legal obligations under the CRPD and other treaties but also restore the ancient constitutional promise: that no person shall be deprived of liberty save by lawful judgment and with equal dignity under the law.

Here's my view on the situation: ⬇️

I wrote this article about the Mental Capacity Act 2005 and how it appears to be discriminatory against people with additional needs. This is unfair and needs to change. The ball is in hands of Parliament and the Judiciary, and I hope they do the right thing with this information. We can't continue like this; it's not fair, and there's millions of British people suffering at the hands of a messy and potentially discriminatory statute, which I argue is used to target disabled people unfairly and without regards to due process required under common law and Clause 29/39 of the Magna Carta 1297 and of 1225. This urgently needs a formal review from our politicians and judges.

I also argue it is discriminatory, as challenging decisions under the Mental Capacity Act 2005 often requires judicial review, which many people targeted unlawfully under this Act are simply not able to do or even afford its costs, allowing violations of the law to go unnoticed and dodging institutions from being held accountable for their actions.

I am for everybody, and I refuse to allow discrimination against people just because they need more support. Having an impairment or disability isn't a choice; people are born with it. No one should be punished for who they are, full stop, and we need to stop being so silent about equal rights for our citizens. There's problems, and those need to stop being overlooked.