Key points to cover
- The site boundary must be secured with appropriate fencing or hoarding — 2m high close-boarded hoarding in urban areas is standard practice
- Under CDM 2015 Regulation 13, the principal contractor must ensure the necessary steps are taken to prevent unauthorised access to the construction site
- The Occupiers' Liability Act 1984 imposes a duty of care to trespassers — the duty is higher where children are concerned because they are less able to appreciate danger
- All access points must be locked and secured outside working hours — gates, scaffold access ladders, and plant cabins
- Excavations, open shafts, and confined spaces must be covered or fenced to prevent falls by trespassers during non-working hours
- Adequate site lighting deters trespassers and helps security patrols identify unauthorised access
- Keys must be removed from all plant and vehicles at the end of each shift to prevent theft and unauthorised operation
Do's and don'ts
Do
- Secure the site perimeter with appropriate fencing or hoarding — minimum 2m high in areas accessible to the public
- Lock all access points, scaffold ladders, and plant cabins outside working hours
- Cover or securely fence all excavations, open shafts, and hazardous areas before leaving site
- Remove keys from all plant and vehicles at the end of each shift
- Report any evidence of trespass or break-in to the site manager immediately
Don't
- Never leave site gates or access points unlocked or propped open outside working hours
- Never leave ladders erected against scaffolds or buildings where they can be used by trespassers to gain access
- Never leave excavations open and unfenced overnight — children can fall in and be unable to get out
- Never leave keys in plant or vehicles — trespassers (including children) have been killed operating stolen plant
- Never assume that 'No Trespassing' signs alone are sufficient — physical barriers are required
Questions to check understanding
Q1: What duty of care does a site operator owe to trespassers?
Show the answer
Under the Occupiers' Liability Act 1984, an occupier owes a duty of care to trespassers if three conditions are met: the occupier is aware of the danger or has reasonable grounds to believe it exists; the occupier knows or has reasonable grounds to believe that someone may come into the vicinity of the danger; and the risk is one against which the occupier may reasonably be expected to offer protection. The duty is higher where children are concerned because they are less able to appreciate and guard against dangers.
Q2: What does CDM 2015 Regulation 13 require regarding unauthorised access?
Show the answer
CDM 2015 Regulation 13 requires the principal contractor to ensure the necessary steps are taken to prevent access by unauthorised persons to the construction site. This means physical measures such as fencing, hoarding, locked gates, and secured access points — not just warning signs. The standard of security must be proportionate to the risk, with higher standards required in areas accessible to the public, near schools, and in residential areas.
Q3: Why are children at particular risk from construction sites?
Show the answer
Children are naturally curious and attracted to construction sites — they see excavations, scaffolding, plant, and materials as exciting places to explore and play. They cannot fully appreciate the dangers of deep excavations, unstable structures, moving plant, or hazardous substances. The law recognises this: the Occupiers' Liability Act 1984 imposes a higher duty of care where the occupier ought to know that children may trespass. HSE guidance HSG151 ('Protecting the public: your next move') covers keeping the public, including children, out of construction sites.
This is general guidance for UK construction sites. Check it against your own risk assessment, method statement and the site before you deliver it.