In the UK, the legal consequences for accidentally poisoning someone with rat poison depend on the level of negligence and whether the incident occurred in a domestic or professional setting. As of 2026, stricter regulations regarding the use and possession of these substances are in effect.
Potential Criminal Charges
- Gross Negligence Manslaughter: If the poisoning results in death due to extreme carelessness (a “gross breach” of a duty of care), you could face a maximum of life imprisonment.
- Offences Against the Person Act 1861: While primarily for intentional acts, if the act was considered “unlawful and malicious” (which can include extreme recklessness), charges under Section 23 (endangering life) can carry up to 10 years’ imprisonment.
2026 Regulatory & Health and Safety Law
If the incident happens in a workplace or professional capacity (e.g., farming, pest control), additional laws apply:
- Health and Safety at Work Act 1974 (HSWA): Breaching duty of care towards employees or the public can lead to unlimited fines and up to two years’ imprisonment.
- COSHH Regulations 2002: Failure to properly assess and control exposure to hazardous substances (like rodenticides) is a crime punishable by unlimited fines.
- New 2026 Certification Rules: Since January 1, 2026, professional users must hold an approved training certificate (such as CRRU-approved training) to purchase or use rodenticides. Using these substances without proper certification or in breach of new outdoor use restrictions (effective 2025) may be used as evidence of negligence in court.
Civil Liability
Regardless of criminal prosecution, you may be sued for civil negligence. Victims can seek compensation for:
- Physical injury or long-term health complications.
- Loss of earnings and medical expenses.
- Psychological trauma.
Summary of Penalties
| Charge | Maximum Penalty |
|---|---|
| Gross Negligence Manslaughter (if death occurs) | Life Imprisonment |
| HSWA Breach (Professional context) | 2 years’ imprisonment / Unlimited fine |
| COSHH Breach | Unlimited fine |
| Negligence (Civil) | Unlimited financial compensation |
If such an accident has occurred, it is critical to seek immediate legal advice and ensure all safety data sheets (SDS) and storage records are available for investigation. You can find more information on HSE.gov.uk.