James Manwaring

I’m a Fellow, Assistant Professor, and Director of Studies in Law at Homerton College, University of Cambridge. Previously I taught at UCL and Hertford College, Oxford. I studied at Warwick and then Oxford.

I work on criminal law, tort law, moral philosophy, and law reform. I’ve published on defences, homicide, mens rea, legal standards, and punishment.

You can find me elsewhere at Cambridge Law, Google Scholar, PhilPeople, LinkedIn, Substack, Wikipedia, Github, and Bluesky.

Papers

  1. ‘Gross Negligence Manslaughter Remade’ (2026) Journal of International and Comparative Law (forthcoming)

    2. Abstract

    Gross negligence manslaughter has never been considered by the UK Supreme Court. It was last considered by the House of Lords in Adomako (1995). That decision identified four elements of the offence: duty, breach, causation, and grossness of breach. Since then, the Court of Appeal has considered, clarified, and tweaked all four elements of the offence, as well as adding a new element: that the breach must give rise to a serious and obvious risk of death. This article traces and evaluates these changes, in comparative context, considering possibilities for reform.

  2. ‘Individualised Standards’ [2026] Criminal Law Review (forthcoming)

    3. Abstract

    The criminal law sets standards. These standards often account for human differences. For example, what counts as ‘reasonable force’ in self-defence differs for adults versus children. Courts and commentators often imply that we face a single question of whether a standard should account for a given attribute. I claim that we should distinguish two questions. Firstly, whether a standard itself is relativised, raised or lowered, to account for an attribute. Secondly, whether an attribute is contextually relevant to whether the defendant met a (perhaps non-relativised) standard. I illustrate the importance of this distinction with examples from across the criminal law: self-defence, loss of control, sexual offences, and driving offences.

  3. ‘Unnecessary Self-defence’ (2026) Oxford Journal of Legal Studies (forthcoming)

    4. Abstract

    Self-defence is traditionally said to contain a necessity requirement, according to which defensive force is lawful only if it is necessary. But the necessity requirement is formulated inconsistently, and these inconsistencies substantially alter the scope of the defence. I explain these inconsistencies in detail and conclude that the law should abandon the necessity requirement altogether. This would not leave a problematic gap in the law, because necessity would remain an important consideration when judging whether any use of force was reasonable.

  4. ‘Review of AP Simester (ed), Modern Criminal Law: Essays in Honour of GR Sullivan (Bloomsbury 2024)’ (2026) Criminal Law and Philosophy (forthcoming)

    5. Abstract

    I review this festschrift in honour of Bob Sullivan, which includes standout chapters on causation, mens rea, precedent, and insanity.

  5. ‘Inferring Culpability from Negligence’ [2025] Singapore Journal of Legal Studies 5-18

    6. Abstract

    Criminal liability often turns on whether the defendant was negligent. You are negligent if you failed to do what the ‘reasonable person’ would have done. This standard is controversial because you might fail to do what the reasonable person would have done through no fault of your own. (Eg if you are unable to live up to that standard.) Andrew Simester has defended the negligence standard while arguing that it should be relativised to account for defendants with low intelligence. I argue that Simester doesn’t offer a compelling argument to relativise negligence to low intelligence but not other shortcomings.

  6. ‘Homicide: Losing Control’ (2024) 83 Cambridge Law Journal 210-213

    7. Abstract

    Harry Turner killed his wife Sally by stabbing her 68 times. At his murder trial, he tried to claim the partial defence of loss of control. This defence has three elements. The trial judge said that none were present. Turner was duly convicted of murder. But the Court of Appeal held that all three elements might be present, and ordered a retrial. In this case note I explain why the Court of Appeal was correct to do so, but only because the law of loss of control is a mess. (Turner was convicted upon his retrial.)

  7. ‘Proportionality’s Lower Bound’ (2021) 15 Criminal Law and Philosophy 393-405

    8. Abstract

    When is punishment proportionate? I claim that punishment isn’t disproportionately harsh if it imposes costs on a person no greater than the costs which they intentionally caused to others. (The titular ‘lower bound’.) I show how this implies that punishments could be significantly harsher than current sentencing rules without being disproportionate. The reason for this is that crimes impose significantly higher costs (on society generally) than is often appreciated.

  8. Capacity and Culpability (DPhil thesis, University of Oxford, 2019)

    Abstract

    How does and how should the criminal law account for human incapacities? I offer a novel taxonomy of relevant rules, distinguishing ‘incapacity doctrines’ from ‘incapacity relativisations’ and ‘counterfactual incapacity relativisations’. I defend the conventional view that being incapable of conforming to a legal norm is a ground for exculpation. I argue (against Gideon Yaffe) that the law is justified in identifying relevant incapacities by proxy attributes. However, where the law requires direct proof of a culpability-reducing incapacity (such as the ability to distinguish right from wrong in the insanity defence), I argue against further requirements to prove that such incapacties derived from a particular aetiology (eg a recognised psychiatric condition). I conclude with a sceptical argument as to whether the metaphysics of capacities can provide any assistance to legal doctrine.

  9. ‘Windle Revisited’ [2018] Criminal Law Review 987 [paywalled version]

    10. Abstract

    The insanity defence is available at common law if the defendant ‘did not know he was doing what was wrong’ (part of the famous M’Naghten rules). English law interprets this very restrictively to mean ‘Did not know it was legally wrong’. I argue that this interpretation was based on flawed reasoning.

Work in progress

Feel free to get in touch for drafts, or to let me know that you are working on these topics.

  1. Paper on complicity 1
  2. Paper on complicity 2
  3. Paper on inchoate complicity
  4. Paper on law reform