The Construction (Design and Management) Regulations 2015 (CDM) don’t require a security guard on site. They never mention guards at all (legislation.gov.uk). What they do require is that the necessary steps are taken to keep unauthorised people off the site (legislation.gov.uk). The Health and Safety Executive (HSE) restated that duty in June 2026, and said it applies both during and outside working hours (HSE).
So the question isn’t whether a guard is compulsory. It’s what “necessary steps” means on your site, and who answers for it.
Who is responsible
CDM puts a duty on each of the main parties:
- The client must take reasonable steps to ensure the principal contractor carries out its duties (legislation.gov.uk). HSE says the client’s pre-construction information should cover boundaries, access and measures to exclude unauthorised people (HSE).
- The principal contractor must ensure the necessary steps are taken (legislation.gov.uk).
- Each contractor must not start work until reasonable steps have been taken (legislation.gov.uk).
What the rules expect at the boundary
Where health and safety makes it necessary, a site must mark its perimeter with suitable signs, be fenced off, or both. That applies so far as is reasonably practicable, and in line with the level of risk (legislation.gov.uk). In populated areas, HSE says that typically means a two-metre high small mesh fence or hoarding around the site (HSE).
Sites on a street have a second rule to meet. Under the Highways Act 1980, anyone putting up or taking down a building on a street, or altering the outside of one, must first put up a close-boarded hoarding or fence (legislation.gov.uk). The local authority has to be satisfied with it, and can agree to do without it (legislation.gov.uk). In London that authority is the borough council, or the Common Council in the City (legislation.gov.uk).
Councils also license hoardings on the public highway. Westminster and Southwark, for example, both require a licence before one goes up (Westminster City Council) (Southwark Council). Westminster attaches specific conditions to each licence (Westminster City Council), so talk to your borough early.
What a secure site looks like day to day
HSE’s steps are aimed mainly at keeping children out, but they work as a closing routine for any site (HSE):
- Secure the site when work finishes for the day.
- Barrier off or cover excavations and pits.
- Isolate and immobilise vehicles and plant, and lock them in a compound if you can.
- Store materials so they can’t topple or roll.
- Remove access ladders from excavations and scaffolds.
- Lock away hazardous substances.
HSE also says to check site security regularly, so that fencing and hoarding stay in good order (HSE).
Scaffolding needs its own attention. HSE’s 2018 safety alert says access must be prevented out of hours, and also when workers are present but out of sight (HSE). Perimeter fencing should be the main defence, with local fencing, ladder removal or locked ladder guards where needed (HSE).
People you do let in need managing too. They can be limited to certain areas, you must explain the site rules to them, and some visitors may need an escort (HSE).
When a security officer makes sense
Fencing and routines are the baseline, and some sites need nothing more. HSE’s alert lists what affects the level of security a site needs (HSE), and these are the factors we’d look at first:
- how close the site is to homes, schools and public venues
- how long it closes for: overnight, a weekend, a holiday or longer
- how quiet or overlooked the access points are
- what’s already there, such as patrols and CCTV
In our view, an officer earns their place in three situations:
- A busy gate. A fence can’t check who or what comes in. An officer can check people, vehicles and deliveries against your lists, and keep the site log.
- A site left empty. Nights, weekends and holiday shutdowns leave nobody to notice a gap in the fence or a door left open.
- An exposed site. Next to homes or schools, or hidden from view, regular recorded patrols show the steps are being taken as well as written down.
A quieter site with a sound perimeter may only need mobile patrols out of hours, or no officer at all. Whatever you choose, no measure stops everyone, as HSE itself accepts (HSE).
Theft is a separate risk
CDM is about safety, not theft, but the same measures help with both. Avon and Somerset Police warn that taking keys out and using padlocks and chains is no longer enough (Avon and Somerset Police). Their advice includes steel hoarding, security lighting that helps CCTV capture clear images at night, timing high-value deliveries to match installation dates, and keeping tools and materials well away from the boundary (Avon and Somerset Police).
Security for your site
Our officers hold valid SIA licences, and we provide construction site security across London, from gate control to out-of-hours guarding and patrols. For a quote, contact us, call 020 8305 1122 or email info@albiz.co.uk.