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Construction Site Health & Safety Law UK (2025)

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Written by Brad Askew Solicitor (non-practising)
Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice.
Updated June 2026 · England & Wales
Building sites carry risks that most other workplaces simply do not. Working at height, moving plant, excavations, live services, noise, dust and manual handling all sit alongside each other, often with several trades operating in the same space. UK law responds to this by placing clear duties on the people who commission, design, manage and carry out construction work. Understanding who is responsible for what, and at which stage of a project, is the starting point for running a site that is both legally compliant and genuinely safer for the people on it. This guide walks through the main statutory duties that apply to construction work in England, Scotland and Wales, explains how the Construction (Design and Management) Regulations 2015 allocate responsibility between duty holders, and sets out the practical steps most sites need to take.

Overview

Construction health and safety law in the UK is a layered system. At the top sits the Health and Safety at Work etc. Act 1974, which imposes broad duties on employers, the self-employed and workers to protect people at work and anyone else affected by work activities.

Beneath that sit regulations that deal with specific risks or sectors. The most important of these for construction is the Construction (Design and Management) Regulations 2015, usually shortened to CDM 2015. These regulations apply to every construction project in Great Britain, from a small domestic refurbishment through to major infrastructure, and they set out who counts as a client, designer, principal designer, principal contractor, contractor or worker, along with what each of them has to do.

Supporting these are general workplace regulations covering risk assessment, work equipment, manual handling, working at height, personal protective equipment, noise, vibration and hazardous substances. Together they create a framework where safety is planned in from the earliest design decisions and managed actively on site, rather than bolted on at the end.

Key steps

  1. Identify the duty holders on your project. Work out who the client, principal designer, principal contractor, designers and contractors are, and record this in writing. On any project involving more than one contractor, CDM 2015 requires a principal designer and principal contractor to be appointed in writing by the client. Getting this right at the outset shapes every other decision.
  2. Carry out and document risk assessments. The Management of Health and Safety at Work Regulations 1999 require a suitable and sufficient assessment of the risks workers and others are exposed to. For construction, this means looking at site-specific hazards such as height, excavation, services, traffic, dust and noise, then recording significant findings and the controls chosen. Review assessments when the work or site changes.
  3. Prepare the construction phase plan. Before any construction work starts, the principal contractor (or the contractor on single-contractor projects) must draw up a construction phase plan setting out how health and safety will be managed. It should be proportionate to the project, cover site rules, welfare arrangements and high-risk activities, and be kept up to date as conditions change.
  4. Provide information, instruction, training and supervision. Workers need to understand the hazards they face and the controls in place. This includes site induction, toolbox talks, task-specific training for activities such as working at height or operating plant, and visible supervision. Competence should be checked, not assumed, and refreshed when equipment, methods or personnel change.
  5. Monitor, report and learn. Inspect the site regularly, act quickly on issues, and record accidents and near misses. Certain incidents must be reported to the Health and Safety Executive under RIDDOR. Use the information you gather to update risk assessments, method statements and the construction phase plan so that lessons flow back into how the site is run.

Common questions

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Common questions

Q Does CDM 2015 apply to small jobs and domestic projects?
Yes. CDM 2015 applies to all construction work in Great Britain, including domestic projects where a homeowner is the client. The duties are scaled to the size and complexity of the project, so a small extension will not need the same paperwork as a commercial build, but the core duties around competence, planning, risk management and welfare still apply.
Q Who is legally responsible if something goes wrong on site?
Responsibility depends on the circumstances. Employers, the self-employed, clients, designers, principal designers, principal contractors and individual workers all carry duties. More than one party can be liable for the same incident. The Health and Safety Executive investigates serious incidents and can bring prosecutions against companies and, where appropriate, individual directors or managers.
Q When does a project need to be notified to the HSE?
Under CDM 2015, a project must be notified to the Health and Safety Executive if construction work is scheduled to last longer than 30 working days and have more than 20 workers working simultaneously at any point, or exceed 500 person days. The client is responsible for making the notification using form F10 before work starts.
Q What welfare facilities must be provided on site?
Sites need suitable toilets, washing facilities with hot and cold water, drinking water, somewhere to change and store clothing, and a warm place to rest and eat. These must be available from the start of the project, not added part way through. The principal contractor or contractor is responsible for ensuring they are provided and maintained.
Q What is the difference between a risk assessment and a method statement?
A risk assessment identifies hazards, who may be harmed and what controls are needed. A method statement, often combined as a RAMS document, sets out step by step how a particular task will be carried out safely using those controls. Method statements are not a strict legal requirement for every task, but they are widely expected for higher-risk work.
Q What happens if the HSE finds breaches during an inspection?
Inspectors can give verbal advice, issue improvement or prohibition notices, or recommend prosecution for serious matters. Prohibition notices stop the activity immediately until the issue is fixed. The HSE can also recover its costs through the Fee for Intervention scheme where it finds a material breach. Check gov.uk for current guidance on enforcement.
Q Do subcontractors have their own duties, or just the main contractor?
Subcontractors are treated as contractors under CDM 2015 and have their own legal duties. They must plan, manage and monitor the work under their control, cooperate with the principal contractor, provide information to their workers, and ensure their own employees are competent. They cannot rely on the principal contractor to discharge their statutory responsibilities.
If you're dealing with this kind of situation, a call with an experienced legal adviser can help you work out the right next step — from £89.

Sources

This guide is based on primary UK law and official guidance.

Brad Askew, Solicitor (non-practising)

Written & reviewed by

Brad Askew Solicitor (non-practising)

Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice. LegalDocuments.co.uk is not a law firm and does not provide regulated legal advice.

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Legal disclaimer
This article is for general information only. It is a tool to help you find your way — not legal advice, and not a substitute for speaking to a qualified adviser about your situation.