Ligature Risk and Safe Staffing on Mental Health Wards: What the 2025 Safety Investigation Found

A 2025 national patient safety investigation into adult mental health inpatient settings, carried out by the Health Services Safety Investigations Body (HSSIB), drew a direct line between understaffing, delayed ligature-point maintenance and avoidable patient harm. For ward managers and compliance leads, its findings are a useful benchmark: they show specifically where inspectors and investigators are now focusing when they assess whether a ward's environment and staffing genuinely support safe, therapeutic care.

Understaffing and ligature risk are directly linked, not separate issues

The investigation found that understaffing contributed directly to patient harm through delayed ligature-point maintenance, reduced observation capacity, and an inability for staff to build the protective therapeutic relationships that reduce risk in the first place. This matters for how services approach ligature risk audits: a ligature risk assessment that only looks at the physical environment, without also examining whether staffing levels allow identified risks to actually be remediated or mitigated on a realistic timescale, is incomplete by the standard this investigation sets.

Nursing vacancy rates vary sharply by region

The report found nursing vacancy rates ranging from 17.4% in the East of England to 11.5% in the North East and Yorkshire — a reminder that national staffing guidance has to be read alongside local workforce reality. It also noted that as experienced nurses have left the sector, a growing share of mental health inpatient staff are newly qualified and lack adequate training in trauma-informed care and therapeutic relationship-building, which the investigation treats as a safety issue in its own right, not just a skills gap.

Built environments: "not therapeutic" in some settings

HSSIB's investigation found that in some settings, the built environment itself was "not therapeutic" and contributed to patient harm, citing estates maintenance challenges — including delayed resolution of identified ligature risks — and capital funding constraints that prevent necessary improvements. For providers, this is a useful framing to bring into internal audits: a ligature risk register with long-outstanding, unresolved items isn't just an estates backlog, it's a patient safety finding in the terms this investigation uses.

The specific recommendations providers should know

Three recommendations from the investigation are particularly relevant to how staffing and environment decisions get made. Recommendation R/2024/037 calls on the Shelford Group to update the Mental Health Optimal Staffing Tool using current acuity data, so that staffing guidance actually reflects patients' real mental and physical health needs rather than outdated assumptions. Recommendation R/2024/039 calls on the Department of Health and Social Care to identify built-environment requirements needed to deliver safe, therapeutic care and to develop strategic capital investment plans to meet them. Recommendation R/2024/040 specifically addresses high-secure service environments, given the particular capital constraints and long-term safety planning those settings require.

Multidisciplinary staffing gaps extend beyond nursing

The investigation also flagged that many wards lack adequate allied health professional input — occupational therapy, speech and language therapy, and dietetic services were all specifically named as under-resourced, limiting patients' access to therapeutic activity and support that contributes directly to safety, not just quality of life. A staffing compliance review that only counts registered nursing numbers is likely to miss this dimension of the investigation's findings.

What this means for your next ligature risk audit

Three practical takeaways follow from the investigation: first, cross-reference your ligature risk register against actual remediation timelines, not just identification dates — a long-outstanding unresolved risk is now a recognised safety investigation finding, not a routine estates matter. Second, benchmark your nursing vacancy rate against your region's reported range and be able to explain what mitigations are in place if you're running above it. Third, don't treat staffing sufficiency and environmental safety as separate audit streams — HSSIB's findings treat them as directly connected.

Frequently asked questions

Is HSSIB's investigation legally binding guidance?
No — HSSIB investigations produce safety recommendations rather than statutory requirements, but CQC inspectors and NHS commissioners treat them as authoritative evidence of expected practice, and providers should expect to be asked how they've responded.

How often should a ligature risk assessment be reviewed?
There's no single fixed national interval specified in this investigation, but best practice — and the standard CQC inspectors look for — is a documented, regularly reviewed risk register with clear remediation timescales and evidence that identified risks are actually being closed, not just logged.

Does this investigation apply to CAMHS wards as well as adult services?
This particular 2025 investigation focused specifically on adult mental health inpatient settings, though its staffing and environmental findings are widely treated as relevant across the broader mental health inpatient sector.

Ward-level safety and environmental compliance is a core ongoing CPD area for mental health inpatient staff and managers. Explore Learnsignal's CPD courses to keep this training current.

Where ligature risk overlaps with wider ward safety duties

Ligature risk assessment doesn't sit in isolation from a ward's other statutory safety obligations. Staff making decisions about environmental risk, and about when and how to intervene physically, are also operating under the same restrictive-practice framework covered by the Mental Health Units (Use of Force) Act 2018 — a reduction in physical intervention achieved by removing a ligature point still has to be documented and justified under that same statutory reporting duty. Similarly, where a patient is admitted via a health-based place of safety under Section 136, the environmental risk assessment for that space is subject to the same ligature-audit principles as the longer-stay ward, even though the person may be there for only a matter of hours. Training that treats ligature assessment as a separate, standalone module — rather than one strand of a connected set of ward safety duties — risks leaving staff able to pass an audit checklist without understanding how the different safety frameworks reinforce each other in practice.