Work that can involve physical intervention and confrontation – standard liability policies are written for accidents, not deliberate acts, so guarding needs its own wording.
In this trade the wording is the product and the paperwork is the defence. Individuals: specialist public liability with deliberate-acts and wrongful-arrest cover, plus personal accident. Companies: £5m/£10m limits, EL covering labour-only subs, inefficacy cover, and incident reports filed religiously – at an £18k average claim, documentation pays for itself the first time it's needed.