CDM 2015 Core · Mandatory · Pre-Construction
CDM Duty Holder Register
The CDM Duty Holder Register records all parties with statutory duties under CDM 2015, including the client, principal designer, principal contractor, designers, and contractors. It provides a single reference point for duty holder contact details, appointment dates, and scope of responsibilities throughout the project lifecycle.
Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. CDM 2015 Reg 5 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.
| What it is | A single, maintained record of every party holding a CDM duty holder role on the project — their role, contact details, and appointment date |
| Explicitly mandated | Not named as a standalone document in CDM 2015 — but required by the practical operation of multiple regulations |
| Practically essential | Yes — the CPP must include project team details; the PCIP requires team information; the F10 requires contact details; HSE inspectors expect it |
| Who maintains it | Typically the Principal Designer during pre-construction, and the Principal Contractor during construction. Client holds the master record. |
| When started | From the first appointment — typically when the client appoints the PD or first designer |
| When updated | Throughout the project as new duty holders are appointed or existing ones change |
| Applies to | All construction projects — proportionate in size to the number of duty holders involved |
1. What Is the CDM Duty Holder Register?
The CDM Duty Holder Register is a single, consolidated record of every organisation or individual holding a CDM duty holder role on a construction project — including their role, contact details, appointment date, and the basis for their appointment.
It is the answer to the question every HSE inspector asks first on arrival at a construction site: ‘Who is the client? Who is the Principal Designer? Who is the Principal Contractor? Who are the designers and contractors on this project?’ The duty holder register consolidates that information into one accessible document.
Not a standalone legal requirement — but functionally essential
CDM 2015 does not name a ‘duty holder register’ as a required document. However, multiple regulations require the same information it contains: the F10 notification requires names and contact details of duty holders; the Construction Phase Plan must record the project team; the PCIP must include project team details; and Regulation 4(8)(a) requires the client to provide information identifying each designer and contractor. In practice, a maintained register is the only efficient way to satisfy all of these overlapping requirements. Every experienced CDM professional maintains one.
2. The Regulatory Web — Why It's Needed
The duty holder register is not driven by a single regulation — it is driven by the cumulative effect of several. Each of the following CDM 2015 provisions requires information about who holds what role, making a central register the only practical way to maintain compliance across the board.
| Regulation | Duty holder | How the register serves it |
|---|---|---|
| Reg 4(1) — Client must appoint PD and PC | Client | The register records when and whom the client appointed, providing auditable evidence of compliance with the appointment duty |
| Reg 4(4) — Pre-construction information | Client | The PCIP must include project team details. The register feeds directly into this section. |
| Reg 4(8)(a) — Client must provide information identifying designers and contractors | Client | The register is the single source of this identification information |
| Reg 6 — F10 notification to HSE | Client | The F10 requires contact details for client, PD, and PC. The register provides the source data. |
| Reg 12(2) — Construction Phase Plan must record arrangements for management of construction work | Principal Contractor | The CPP project organisation section draws directly from the register |
| Reg 11(4) — PD must assist client in providing pre-construction information | Principal Designer | The PD needs to know who has been appointed to ensure information reaches the right parties |
| Reg 8(3) — Appointing party must be satisfied as to competence | All appointing parties | The register records the basis for each appointment, supporting the competence check audit trail |
The practical consequence of not having a register is that these obligations are met piecemeal — or not at all:
- No one can confirm at a glance who currently holds each CDM role, leading to confusion about who is responsible for what
- The F10 notification is submitted with incomplete or outdated contact details, which the HSE will query
- The Construction Phase Plan project team section contains stale information because there is no live source to update from
- When duty holders change mid-project — which is common — the outgoing party's details are lost and the incoming party's appointment is not formally recorded
- HSE inspectors arriving on site cannot be given a quick, clear answer about who holds each role — a red flag that invites closer scrutiny
- The client cannot demonstrate to an adjudicator or court that they fulfilled their duty to appoint competent persons, because there is no consolidated appointment record
3. Who Appears in the Register?
The register should include every party who holds a CDM duty holder role on the project. The scope varies depending on the project type and the number of contractors involved.
| Project type | Who appears | Typical size |
|---|---|---|
| Single contractor project | Client, Designer(s), Contractor | 3–5 entries |
| Multi-contractor project (not notifiable) | Client, Principal Designer, Principal Contractor, all Designers, all Contractors | 6–15 entries |
| Notifiable multi-contractor project | Client, Principal Designer, Principal Contractor, all Designers, all Contractors, CDM Advisor (if appointed) | 10–50+ entries |
A note on combined roles:
On smaller projects, one organisation may hold more than one CDM role. A design-and-build contractor, for example, may act as both Principal Designer and Principal Contractor. An architect on a domestic extension may be the only designer and also fulfil the PD function. In these cases, the register should still list each role separately, noting the same organisation against each. This makes it clear that the duties of each role have been consciously allocated — rather than falling through the cracks because no one considered who was responsible for them.
Record the named individual, not just the organisation
CDM 2015 duties attach to organisations, but they are discharged by individuals. A register that records only ‘ABC Architects Ltd’ without identifying the named person responsible is incomplete. HSE inspectors will ask for the individual — not the company switchboard number. Best practice is to record both the organisation and the named individual who will be the day-to-day point of contact for that CDM role, along with their direct contact details.
4. What Should Each Entry Record?
Each entry in the register should capture enough information to identify the duty holder, their role, how to contact them, and the basis for their appointment. The following fields represent best practice for a comprehensive register.
| Field | What to record | Required |
|---|---|---|
| CDM role | The specific duty holder role: Client, Principal Designer, Principal Contractor, Designer, or Contractor | Yes |
| Organisation name | The registered company or trading name of the appointed organisation | Yes |
| Company registration number | Companies House number — useful for formal identification and audit | Recommended |
| Named individual | The person within the organisation who will discharge the CDM duties day-to-day | Yes |
| Job title | The individual’s role within their organisation (e.g. Project Director, Site Manager) | Recommended |
| Phone number | Direct phone number for the named individual — not a general switchboard | Yes |
| Email address | Direct email for the named individual | Yes |
| Registered address | The organisation’s registered or principal office address | Recommended |
| Date appointed | The date on which the duty holder was formally appointed to the CDM role | Yes |
| Appointment basis | Reference to appointment letter, contract clause, or written confirmation | Recommended |
| Date ceased (if applicable) | The date a duty holder’s appointment ended, if they have been replaced or the role transferred | If applicable |
Example register entries (for illustration):
The following table shows how a typical register might look on a mid-sized commercial project with multiple duty holders. This is illustrative — actual projects will vary in the number and type of entries.
| CDM Role | Organisation | Named person | Phone / Email | Appointed |
|---|---|---|---|---|
| Client | Northfield Developments Ltd | Sarah Mitchell | 07700 900123 / s.mitchell@northfield.co.uk | 01 Feb 2026 |
| Principal Designer | Clarke Partnership Architects | James Clarke | 07700 900456 / j.clarke@clarkepartnership.co.uk | 15 Feb 2026 |
| Principal Contractor | Hargreaves Construction Ltd | David Turner | 07700 900789 / d.turner@hargreaves.co.uk | 01 Mar 2026 |
| Designer (Structural) | MBS Consulting Engineers | Priya Sharma | 07700 900234 / p.sharma@mbsconsulting.co.uk | 20 Feb 2026 |
| Designer (M&E) | Wallace Services Design | Tom Wallace | 07700 900567 / t.wallace@wallacesd.co.uk | 22 Feb 2026 |
| Contractor (Demolition) | Kellaway Demolition Ltd | Mark Kellaway | 07700 900345 / m.kellaway@kellaway.co.uk | 10 Mar 2026 |
| Contractor (Groundworks) | Ridgeway Civil Engineering | Ian Frost | 07700 900678 / i.frost@ridgewayce.co.uk | 15 Mar 2026 |
5. When Is It Started and Who Maintains It?
The register should be started as soon as the first CDM appointment is made — typically when the client appoints the Principal Designer or the first designer. It is then maintained throughout the project lifecycle, with responsibility for day-to-day upkeep passing between the PD and PC as the project moves from pre-construction to construction.
| Stage | What happens |
|---|---|
| At first appointment | The register is created when the client makes their first CDM appointment (usually the PD or first designer). The client’s own details are the first entry. |
| During pre-construction | The Principal Designer maintains the register, adding designers and any early contractor appointments. The register feeds into the PCIP project team section. |
| During construction | The Principal Contractor takes over day-to-day maintenance, adding contractors and subcontractors as they are appointed to the project. |
| On duty holder changes | When a duty holder is replaced or their role changes, the register is updated immediately. The outgoing party’s entry is marked with a cessation date, and the incoming party is added. |
| At practical completion | The final version of the register is included in, or referenced by, the Health and Safety File as a permanent record of who held each CDM role during the project. |
| Format | There is no prescribed format. A simple table — spreadsheet, PDF, or digital register — is sufficient. What matters is that it is maintained, accessible, and current. |
6. How It Links to the F10 Notification
The F10 notification — the formal notification to the HSE required on notifiable projects under CDM 2015 Regulation 6 — requires the client to provide contact details for the client, Principal Designer, and Principal Contractor. The duty holder register is the natural source of this information, and keeping the two aligned prevents the common problem of the F10 containing outdated or inconsistent details.
- The F10 draws its duty holder contact details directly from the register — the register is the ‘single source of truth’ and the F10 is a downstream output
- When the PD or PC changes during the project, the F10 must be updated and re-submitted to the HSE — the register triggers this by recording the change
- The initial F10 should be submitted as soon as is practicable before the construction phase begins — the register must therefore be populated before the F10 is filed
- The HSE expects the F10 details to match the reality on site — if an inspector finds different people in charge than those named on the F10, it indicates a failure of record-keeping
- On projects where the F10 is filed electronically, cross-referencing the register ensures the submitted data is accurate and consistent with other project documents
The register and the CPP project team section
The Construction Phase Plan is required to set out the arrangements for managing the construction work, which includes identifying the project team. The CPP project team section should be populated from the duty holder register — not maintained separately. When the register is updated, the CPP should be updated to match. Maintaining two independent lists of duty holders is a common source of inconsistency that the HSE will identify during an inspection.
7. Common Mistakes
Not creating one at all
The most common mistake. Because the register is not named as a standalone requirement in CDM 2015, many projects simply do not have one. The result is that duty holder information is scattered across appointment letters, contracts, the F10, and the CPP — with no single point of reference and no mechanism for keeping it current.
Recording the organisation but not the named individual
A register that lists ‘Smith & Jones Architects’ without identifying the specific person responsible is incomplete. CDM duties are discharged by individuals within organisations. HSE inspectors expect to know who, specifically, is fulfilling each role — not just which company was appointed.
Not updating it when duty holders change
Duty holders change during projects — the PD firm may be replaced, a contractor may go into administration, a named individual may leave their organisation. If the register is not updated, every document that draws from it (F10, CPP, PCIP) becomes stale. This is a compliance failure that is immediately visible to an inspector.
Confusing CDM roles with contractual roles
A ‘project manager’ is not a CDM role. A ‘CDM advisor’ is not a statutory duty holder. The register should record CDM 2015 duty holder roles — Client, Principal Designer, Principal Contractor, Designer, Contractor — not contractual titles. Conflating the two creates ambiguity about who holds the legal duty.
Failing to record the appointment date
The date of appointment is essential evidence that duty holders were appointed before work that required their role commenced. Without it, the client cannot demonstrate compliance with the timing requirements of CDM 2015 Regulation 5. A register without dates is an audit trail without a timeline.
Keeping it in a format that is not accessible on site
If the register exists only as a file on someone’s laptop or buried in a project management system that site staff cannot access, it fails its primary purpose. The register must be available to anyone who needs it — including HSE inspectors arriving unannounced. It should be available on site, either in hard copy in the site office or accessible digitally.
9. Frequently Asked Questions
Is a CDM Duty Holder Register a legal requirement?▾
Not as a named standalone document. CDM 2015 does not prescribe a ‘duty holder register’ by name. However, the information it contains is required by multiple regulations — the F10, the CPP, the PCIP, and the general duty to identify designers and contractors. In practice, maintaining a register is the only efficient way to meet these overlapping requirements, and HSE inspectors expect to see one on any well-managed project.
Who is responsible for maintaining the register?▾
There is no single prescribed owner. In practice, the Principal Designer typically creates and maintains it during pre-construction, and the Principal Contractor takes over during the construction phase. The client should hold the master record throughout and ensure it is kept current — as the client holds the overarching duty to ensure suitable management arrangements are in place.
Does the register need to include subcontractors?▾
Yes. Any organisation carrying out construction work on the project is a ‘contractor’ under CDM 2015, regardless of their position in the contractual supply chain. Subcontractors, sub-subcontractors, and specialist trade contractors all hold CDM duties and should appear in the register.
What happens if a duty holder changes mid-project?▾
The outgoing duty holder’s entry should be marked with a cessation date, and the incoming duty holder added with their appointment date. The F10 must be updated and re-submitted to the HSE if the client, PD, or PC changes. The CPP project team section must also be updated to reflect the change.
Can the register be a spreadsheet?▾
Yes. There is no prescribed format. A spreadsheet, a table in a Word document, a PDF, or a digital register within a project management system are all acceptable. What matters is that it is maintained, accessible, accurate, and available to anyone who needs it — including HSE inspectors. A digital format that supports version control and access logging is ideal.
Should a domestic client keep a duty holder register?▾
For most domestic projects the register will be very simple — perhaps only two or three entries. But the principle still applies: someone needs to know who is acting as designer, who is the contractor, and who holds the client’s transferred duties. On a domestic project with multiple contractors, the principal contractor inherits the client’s duties and should maintain a record of who is working on the project and in what capacity.
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Get started freeThis guide is for general informational purposes only and does not constitute legal advice. While every effort is made to ensure accuracy, regulations change and individual project circumstances vary. Construction Suite is a trading name of Xzist Digital Ltd, registered in England and Wales.