CDM principal contractor duties: full list of responsibilities under CDM 2015

Who is the principal contractor

The principal contractor is the contractor appointed by the client to plan, manage, and monitor the construction phase of a project where more than one contractor is involved. On a single-contractor project, that contractor automatically assumes the principal contractor duties.

The appointment must be in writing, and the client must ensure the appointee has the skills, knowledge, experience, and organisational capability to carry out the role. In practice, the principal contractor is usually the main contractor on the project, but it can be any contractor the client appoints.

The appointment must happen before the construction phase begins. If the client fails to appoint a principal contractor, the duties default to the contractor in control of the construction work. This is not a comfortable position to be in accidentally, so the appointment should always be formalised.

Planning the construction phase

The principal contractor must prepare a construction phase plan before the construction phase begins. This is not a generic health and safety policy: it is a site-specific document that sets out how health and safety will be managed on this project. The plan must include:

• A description of the project: What is being built, the key phases, the expected duration, and the anticipated peak workforce numbers.
• Management structure: Who is responsible for what. Names, not just job titles. The site manager, safety advisor, first aiders, fire wardens, and the person with overall responsibility for the project.
• Arrangements for managing risks: How the significant risks on this project will be controlled. This includes specific arrangements for high-risk work such as working at height, excavations, lifting operations, demolition, and work near services.
• Site rules: PPE requirements, access restrictions, speed limits, working hours, welfare arrangements, permit-to-work requirements.
• Emergency procedures: Fire evacuation, first aid, rescue from height or confined space, muster points, and communication arrangements.
• Arrangements for monitoring: How the principal contractor will check that the plan is being followed. Inspection schedules, audit frequency, near-miss reporting, and corrective action processes.

The plan is a living document. It must be reviewed and updated as the project progresses, as risks change, and as new contractors arrive on site. A construction phase plan written on day one and never updated is a compliance failure.

Managing and monitoring site safety

The principal contractor must actively manage and monitor the construction work. This goes beyond writing a plan: it means ensuring that the plan is being followed on the ground, every day.

In practice, this includes:

• Regular site inspections by competent people
• Monitoring contractor method statements and risk assessments against actual working practices
• Intervening when standards fall: stopping work if necessary, issuing corrective actions, and following up to confirm they have been implemented
• Reviewing incident and near-miss reports and implementing lessons learned
• Ensuring welfare facilities are maintained and adequate for the workforce
• Confirming that all workers on site hold the appropriate qualifications and certifications for their work

The principal contractor cannot simply leave safety management to each subcontractor. While subcontractors have their own duties under CDM 2015, the principal contractor must monitor their performance and take action where it falls short.

Coordination between contractors

On a multi-contractor site, one of the principal contractor's most important duties is coordination. Different trades working in the same area create interface risks: a steelwork gang working above a finishing team, electricians and plumbers working in the same ceiling void, excavation work near live services.

The principal contractor must:

• Ensure contractors cooperate with each other and coordinate their work
• Manage the sequencing of work to avoid clashes and interface risks
• Chair coordination meetings and ensure all relevant contractors attend
• Communicate changes in programme, site layout, or access arrangements to all affected contractors
• Resolve disputes between contractors about access, sequencing, or shared resources

Poor coordination is a root cause of many construction incidents. Two contractors working in the same space without knowing about each other is a recipe for an accident. The principal contractor's coordination role is not administrative: it is safety-critical.

Site inductions and information

The principal contractor must ensure that every worker on site receives a suitable site induction before they begin work. The induction must cover site-specific hazards, emergency procedures, site rules, and welfare arrangements. It must be appropriate to the risks on the site, not a generic presentation.

Beyond the initial induction, the principal contractor must also ensure that workers receive ongoing information about changes to site conditions, new hazards, and updated procedures. Toolbox talks, safety briefings before new phases of work, and updates to the site induction content all fall under this duty.

For a detailed guide on site induction requirements and how to deliver them effectively, see our guide to running site inductions in the UK.

Worker consultation

CDM 2015 requires the principal contractor to make arrangements for consulting and engaging with workers on matters affecting their health, safety, and welfare. This is not a suggestion: it is a legal duty.

In practice, this means:

• Establishing a mechanism for workers to raise safety concerns without fear of reprisal
• Appointing or facilitating the election of worker safety representatives
• Holding regular safety forums or committee meetings where worker representatives can raise issues
• Responding to worker concerns and feeding back what action has been taken
• Involving workers in the development of risk assessments and method statements where practical

Worker consultation is not just a compliance box to tick. Workers on the tools see hazards that managers in the site office do not. An effective consultation process surfaces problems early, before they become incidents.

Liaison with the principal designer

The principal contractor must liaise with the principal designer throughout the construction phase. The principal designer is responsible for identifying, eliminating, and controlling foreseeable risks arising from the design. The principal contractor needs to understand what those risks are and how they affect the construction work.

Key areas of liaison include:

• Receiving and acting on pre-construction information from the principal designer
• Feeding back information about site conditions that may affect the design
• Ensuring that design changes during the construction phase are assessed for safety implications
• Providing information to the principal designer for the health and safety file

The health and safety file is a document that the principal designer compiles for the client. It contains information about the completed project that will be needed for future maintenance, cleaning, refurbishment, or demolition. The principal contractor must provide relevant information to the principal designer for inclusion in the file.

Record keeping

The principal contractor must maintain records that demonstrate compliance with their CDM duties. These include:

• The construction phase plan and all updates
• Site induction records for every person who has worked on site
• CSCS card and competency verification records
• Risk assessments and method statements from all contractors
• Site inspection reports and corrective action records
• Incident, accident, and near-miss reports
• Worker consultation records (minutes of safety meetings, concerns raised, actions taken)
• Training records for site-specific training delivered
• Permits to work issued and closed out

These records must be available for HSE inspection at any time during the project. They should also be retained after the project ends, typically for at least six years (the limitation period for civil claims) and longer if the project involves work that could have long-latency health effects (such as asbestos).

Managing this volume of records on paper is increasingly impractical, particularly on large multi-contractor sites. AttendIQ centralises induction records, competency verification, attendance tracking, and compliance documentation in one platform, making it straightforward to produce the records an HSE inspector or client auditor expects.

Enforcement and consequences

HSE enforces CDM 2015 through inspections, investigations, and enforcement action. The consequences of non-compliance are serious:

• Improvement notices: Requiring the principal contractor to remedy a specific breach within a set timeframe.
• Prohibition notices: Stopping specific work or all work on site until the danger is removed. A prohibition notice means workers go home and the programme stops.
• Prosecution: For serious breaches, HSE can prosecute the organisation and, in some cases, individual directors or managers. Fines are unlimited. For fatalities, individuals can face imprisonment.
• Fee for Intervention (FFI): If HSE identifies a material breach during an inspection, they charge the duty holder for the time spent on enforcement activity. This is currently 163 per hour.

Beyond formal enforcement, HSE publishes details of prosecutions, convictions, and fines. The reputational damage from a published prosecution can affect a contractor's ability to win work for years.

The best protection is not legal advice after an incident: it is having the systems, processes, and records in place that demonstrate you take your duties seriously and manage safety proactively. For a broader look at CDM compliance, see our CDM 2015 guide for contractors.