What Is L153? The HSE Guidance Behind CDM 2015

A practical guide for UK site managers, contractors and small builders.

If you have spent any time reading about CDM 2015, you will have seen the reference L153 crop up again and again, usually without anyone explaining what it actually is. It sounds like a regulation number or a form you are supposed to fill in, and it is neither. L153 is the official HSE guidance document that sits behind the CDM 2015 regulations and tells you, in plain terms, how to meet your duties. This guide explains what L153 is, what it covers, what legal weight it carries, and how to use it on a real project without getting lost in it.

What is L153?

L153 is the Health and Safety Executive publication titled Managing health and safety in construction, and it is the guidance to the Construction (Design and Management) Regulations 2015. The L in the reference is simply how the HSE numbers its legal series publications, and 153 is the number of this particular document. When people talk about looking up something in CDM, more often than not the book they actually need is L153, because it is the plain-English companion to the regulations themselves.

Put simply, the regulations are the law and L153 is the manual that explains how to follow it. It takes each duty in CDM 2015 and sets out what a sensible, proportionate response looks like, so that a client, designer or contractor can read it and understand what is expected of them without needing a lawyer to translate.

What L153 covers

L153 walks through CDM 2015 in the order the regulations are laid out, and it is organised around the people who carry duties. The main areas it deals with are:

• The duty holders and their roles. It explains what is expected of the client, the principal designer, designers, the principal contractor, contractors and workers, and how those roles fit together on a project.
• Getting a project set up correctly. It covers appointing the right people, gathering and sharing pre-construction information, and making sure everyone understands their part before work starts.
• Planning and managing the work. It describes the construction phase plan, how site risks should be managed, and what proportionate planning looks like for both small and large jobs.
• Welfare and site standards. It sets out the welfare facilities that must be provided and the general standards expected on site.
• The health and safety file. It explains what information should be gathered and handed over so a structure can be maintained and altered safely in future.

Crucially, it does all of this with an eye on proportionality. L153 repeatedly makes the point that the effort you put in should match the size and risk of the job, which is one of the most useful things it does for smaller builders who worry they are supposed to produce reams of paperwork for a modest project.

What legal status L153 carries

This is the part that trips people up. L153 is guidance, not an Approved Code of Practice. That distinction matters. Under the previous CDM regime there was an Approved Code of Practice, which carried a special quasi-legal status: if you were prosecuted and had not followed it, the burden fell on you to prove you had complied with the law some other way. CDM 2015 has no Approved Code of Practice; the old one was withdrawn and replaced with L153 guidance instead.

Because L153 is guidance, following it is not itself a legal requirement. What you must do is comply with the regulations. But L153 is the HSE telling you, in its own words, how it expects those regulations to be met, so following it is strong evidence that you are meeting your duties. An inspector will broadly expect your approach to line up with L153, and departing from it without a good reason is a difficult position to defend.

How to actually use L153 on site

The mistake is to treat L153 as something to read cover to cover once and never open again. It works far better as a reference you dip into. When you take on a new role or hit a question about who is responsible for what, go to the section for that duty holder and read what it says a proportionate response looks like. When you are putting a construction phase plan together, use its description of what the plan should contain as your checklist.

The practical goal is not to memorise L153 but to make sure the things you do on site line up with it: appoint the right people, share the pre-construction information, produce a construction phase plan before work starts, manage the risks and provide welfare, and keep the records that show you did. Do those things in the way L153 describes and keep the evidence, and you have a defensible, compliant project.

Frequently asked questions

This article is general guidance for UK construction and is not legal advice. For requirements specific to your work, check the full text of CDM 2015 and current HSE guidance L153, along with your own duty holder obligations.