Mental Health and Capacity Law

This page is just some of the various Acts of Parliament, Codes of Practice and other materials which may be required when navigating mental health and capacity law. Inevitably, there are many more statutes which influence the resources highlighted below. Chief amongst these are the Human Rights Act 1998 and the Health & Safety at Work Act 1974.

At the bottom of the page are some of the more important pieces of caselaw which have emerged around policing and mental health.  Again, these are just some of the cases which I could have listed but I have focussed on the examples I would have wanted to know when I was working operationally 24/7.

England and Wales

  • Mental Health Law – a quick, online reference tool to the Mental Health and Capacity Acts as well as to caselaw and other guidance.


Northern Ireland

Isle of Man


These cases are the absolute “must knows” for operational police officers, including custody officers and criminal investigators.  I am motivated to produce this blog because I keep hearing of police activity which contravenes the following judgments and I keep screaming at Twitter and emails “No!!!! – Hicks v the Commissioner!” and similar.  And just to imply the importance I place upon front line cops knowing this, I’ve put them in what I see as an order of importance – just in case you get bored half way through and drift back to your Jane Austin or your Andy McNAB!

  • Hicks v Commissioner of the Met (2014) – Where officers are contemplating arresting someone to prevent or apprehend a Breach of the Peace, they must have it in mind at the point of arrest to bring that person before a Magistrate as a competent legal authority. Where this was not the intention, the arrest would violate Article 5 of the ECHR.  This case was not, specifically, about mental health but it is an Appeal Court judgment which has bearing on all arrests to prevent or apprehend Breaches of the Peace (BoP).  We know from history that officers often use BoP as a proxy in the absence of other powers: removal to police custody to prevent someone harming themselves, in order to ensure they can be assessed by a Doctor and, if need be, under the Mental Health Act.  This case now shows that such action is unlawful, unless the arresting officer has it in mind to place the person before a Magistrate.  To see an example of where this may have gone wrong, after the ruling, we need only reflect on the incident of a 16yr old girl in Devon custody for two days during December 2014 — the full court judgment.
  • Webley v St George’s (2014) – Where a duty of care has been assumed for a detained person, it is vital that when handing over responsibility for that person you do so to a competent, willing and informed authority.  A failure to do so would amount to negligence on the part of police officers.  This case was about a ‘sectioned’ patient being transferred to hospital by the police for admission who was diverted to A&E because of having a fit in the ambulance.  Officers arranged to handover detention to hospital security, who agree to take over responsibility, and they fully briefed them about background.  Officers were found to have discharged their duty of care despite the fact that patient went on to seriously injure himself — the full court judgment.
  • Sessay v South London and Maudsley & the Met Commissioner (2010) – officers attending a mental health emergency in the claimants private premises were wrong to rely upon the Mental Capacity Act 2005 to defend their actions, when they removed her from her home and took her to the local Mental Health Act place of safety for assessment.  In this judgment, the court reminded us all that the proper legal process for responding to mental health emergencies in someone’s home where there are no criminal offences or urgent, life-threatening risks, is to solicit the support of an AMHP and a DR and request consideration of an urgent assessment under s4 MHA.  There are various problems in reality with this ruling, given the resourcing of duty AMHP services, especially out of hours — the full court judgment.
  • MS v UK (2012) – In 2004 a man who had been detained in police custody as a place of safety under s136 MHA was subject to an inordinate delay in being admitted to hospital after being assessed under the Mental Health Act.  During that time, his personal welfare, his psychiatric condition physical condition deteriorated to such a degree that he was naked in a cell – having soiled his clothing and used it to try to self-harm – and he wasn’t eating or drinking.  The failing to expedite his admission to hospital when he was detained in police custody and in ‘dire need of psychiatric care’ was ruled to be a violation of Article 3 of the European Convention.  This case raises questions about the dignity of patients when they are detained in police custody, especially for protracted periods of time — the full court judgment.
  • R (Munjaz) v Ashworth Hospital Authority (2005) – This is one of the more important things to know about, when police officers are engaging with mental health services who want to manage patients or incidents in contravention of the Code of Practice to the Mental Health Act.  This case was nothing to do with the police: it focussed upon a patient in Ashworth high secure hospital who was ‘secluded’ as part of his treatment.  His seclusion was done in such a way as to deliberately violate the Code of Practice (1999) to the Mental Health Act 1983 and he brought legal action against the hospital.  He initially lost his case, but appealed and won.  The hospital then appealed to the House of Lords because there were different views amongst the various lower judges as to what legal significance a Code of Practice had – was it ‘binding instructing’ that must be followed or ‘mere advice’ that could be disregarded somewhat casually.  Unsurprisingly the House of Lords (now the Supreme Court) took a position between those two arguments, but nearer to ‘binding instruction’ – the court ruled that a Code of Practice was statutory guidance that must be followed unless there are ‘cogent reasons’ for departure and it was up to the departing professional or organisation to justify their actions, case by case — the full court judgment.
  • D’Souza v DPP (1992) – This case concerend police officers forcing entry to a premises under s17 PACE in order to re-detain a section 3 Mental Health Act patient who was AWOL under the Act.  They argued that the patient being in need of compulsory medical treatment meant her life was at risk and therefore that s17 PACE was engaged.  A civil action was brought by the patient and the court agreed with her position that the threshold for forcing entry was not met – despite being a sectioned patient, despite being unwell in the opinion of her psychiatrist, her life was not at imminent risk and officers should have obtained a warrant under s135(2) MHA in order to force entry and return her — the full court judgment.
  • Syed v DPP (2010) – This is another case that was not specicially about mental health issues, but concerned the police use of s17 PACE to justify there is no power of entry under s17 for what we might term ‘welfare checks’.  The threshold for ‘life and limb’ entry is a high and literal one: officers must have reasonable grounds to suspect that someone’s life is literally in danger and cannot enter premises just to check on occupants following reports of a disturbance — the full court judgment.
  • R(B) v CPS (2009) – this is a really important case for criminal investigators who have victims or witnesses who suffer from mental health problems.  In this case, the victim had suffered 18 GBH injuries when his ear was partly bitten off.  As the trial was about to begin, prosecution counsel dropped the case on the basis of a psychiatric report, arguing that that the victim would be an unreliable witness.  There was little objective reason to suppose unreliability, the main emphasis being the victim’s diagnosis of paranoid schizophrenia.  In bring a judicial review, the victim successfully argued that his rights were violated under disability discrimination law and under Article 3 of the European Convention — the full court judgment.
  • Seal v Chief Constable of South Wales Police (2010) – this case was about a failure to seek leave under s139 of the Mental Health Act before bringing a civil action against the police for an ostensibly illegal use of s136.  The claimant was never able to have his substantive allegations heard because he failed to comply with s139 and his various appeals – including to the European Court – failed in arguing against s139 of the Act.  In passing, Lady Justice HALE remarked in one of the earlier British court hearings that to arrest a man in a private dwelling to prevent a Breach of the Peace only to then de-arrest him outside then apply s136 MHA would stand a good chance of being ruled unlawful — the full court judgment.
  • ZH v the Met Commissioner (2012) – in this case a 16yr old boy with severe autism was on a school trip to the local swimming pool in Ealing, London and as they group made to leave, went and stood by the side of the pool, staring at the water.  This was not unusual behaviour for him, as he often fixated at water and usually did so for 15-20 minutes before moving away.  The pool manager was not happy at this actions and called the police, asking for him to be moved.  Without taking advice or guidance from staff present, officers approached him and when they touched him on his back, to encourage him away from the water, he jumped in.  Lifeguards were there as a contingency and formed something of a cordon to move him towards the shallow end and officers pulled him from the water, restrained and handcuffed him before placing him in a police van, still wet.  After a short while, they completely released him and he left the swimming pool with school staff.  His family brought proceedings against the Metropolitan Police Commissioner for assault, battery and violation of human rights laws and were successful, including when the Commissioner appealed against the initial verdict.  The court emphasised that officers were wrong to rely upon the Mental Capacity Act 2005 in justifying their actions — the full court judgment.

These are my top ten important case-law judgments and the implications of them need to be understood by all operational officers working at this interface.  It is from knowledge of these rulings that repeated instances of illegal activity and / or detention will be avoided.  In particular, officers and their supervisors really need to get grips with the Hicks v Commissioner case, because Breach of the Peace has been used and misused for years, to circumvent other procedures and laws, often for noble reasons to do with inability to access other services.  Whilst this intention is fine, these cases show that the practice is not and it does need to stop.

Instead, officers and their supervisors need to ensure that those organisations and other professionals who are responsible for certain public law functions are given the opportunity to discharge their responsibilities and are made to be accountable for them.  Any difficulties need to be flagged to force mental health liaison officers to be discussed with mental health trusts, local authorities and Clinical Commissioning Groups, etc..  If you put your fingers in a mangle, you shouldn’t be surprised to find that you end up dragged in up to the shoulder and that it smarts a bit!

As an Inspector said on my second day in policing:  “Knowledge is confidence and confidence is power.”  I still think he was right – so get knowledge.

Winner of the President’s Medal,
the Royal College of Psychiatrists.

Winner of the Mind Digital Media Award


All views expressed are my own – they do not represent the views of any organisation.
(c) Michael Brown OBE, 2021

I try to keep this blog up to date, but inevitably over time, amendments to the law as well as court rulings and other findings from inquests and complaints processes mean it is difficult to ensure all the articles and pages remain current.  Please ensure you check all legal issues in particular and take appropriate professional advice where necessary.

Government legislation website –


9 thoughts on “Mental Health and Capacity Law

  1. I’d missed this page – unless it’s just appeared.
    Either way – good stuff. Keep the resources coming. I find having a page like this is one of the best ways to keep my blog useful. I’m sure you’ll find the same.

  2. This is very useful, I am currently setting up a group website, can I put some of the information on there? I will say that the info was taken from this site.

    Many Thanks,

  3. Basically – if you are mentally ill you will be treated disgracefully by the Police, more than likely beaten up in a cell. How many have died in this way, whilst the custody sergeant “looks the other way”? After all, who is going to believe someone is mentally ill? Criminalising someone having a mental health issue be at home or in public is the sort of police state we are now in. This whole blog emphasises that giving someone with a mental health crisis “a bit of a hammering” is absolutely acceptable as it passes a few minutes. A disgrace. Given that the police is freemason run, no wonder the freemason judges also make sure the officers involved are found not guilty….

  4. You have already stated yourself it is right to criminalise the mentally ill. They haven’t broken the Queen’s peace nor breached common law, but you, you believe it’s right to criminalise them for it. Would you criminalise someone for having cancer, would you arrest someone for having a cardiac arrest in the street? I know you’ll probably track my IP address and pass it on to your pals so I’ll get a pasting, but really, you are a disgrace.

    1. You’ve badly misunderstood what I’ve said: I argued that it can be appropriate to criminalise mentally ill people who break the law. In just the same way, it can be appropriate to criminalise a cancer patient who breaks the law – all cases turn on their merits so it depends on what people have done as to whether prosecuting them is appropriate. Nobody, anywhere said anything about criminalising people for its own sake but I would add this: some mental health patients argue that the very process of being policed when in crisis is, of itself, criminalising and stigmatising. There is more than one way in which the word ‘criminliase’ is bandied about.

      And for what it’s worth, nobody’s IP address was tracked or even cared about, the provision of this response! You’re quite welcome to leave comments here without fear of anything other than a response like this.

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