Yes. Under CDM 2015, the same organisation can be both the Principal Contractor and the Principal Designer. The Health and Safety Executive expressly allows an organisation or individual to carry out more than one dutyholder role, provided they have the skills, knowledge, experience and organisational capability needed for each role.
There is a bigger test than the company name on the appointment, however. To be Principal Designer, the contractor must qualify as a designer under the Construction (Design and Management) Regulations 2015 and have control over the pre-construction phase. It must also be capable of carrying out the Principal Designer duties as well as its separate Principal Contractor duties during construction.
That makes combined appointments entirely possible on design-and-build projects, but a Design and Build contract does not automatically turn the main contractor into the CDM Principal Designer.
Active construction works on a London site in October 2026, with scaffolding and a tower crane in operation. Photo: London Construction Magazine.
CDM 2015 allows one organisation to hold both roles
The legal starting point is Regulation 5 of the Construction (Design and Management) Regulations 2015. Where a project involves, or is reasonably foreseeable to involve, more than one contractor, the client must appoint in writing a designer with control over the pre-construction phase as Principal Designer and a contractor as Principal Contractor.
Nothing in Regulation 5 says those appointments must go to different organisations. HSE's summary of CDM dutyholder responsibilities goes further and confirms that organisations or individuals can carry out more than one dutyholder role where they have the necessary capability.
The two appointments still carry different statutory functions. The Principal Designer plans, manages, monitors and coordinates health and safety during the pre-construction phase. The Principal Contractor performs the equivalent management and coordination role during the construction phase. LCM's separate guides examine the Principal Designer duties under CDM and the evidence expected from a Principal Contractor in more detail.
The contractor must still qualify as a designer
This is the part that can rule out a combined appointment. CDM defines a designer broadly: it includes organisations that prepare or modify designs and those that arrange for or instruct people under their control to carry out design work. HSE specifically says contractors, specialist contractors and tradespeople can be designers when they become involved in design.
A Principal Designer must then be the designer with control over the pre-construction phase. HSE says the role does not have to personally produce the drawings, but it must be able to control and coordinate the design-stage health and safety process.
That suits many design-and-build arrangements where the main contractor takes control of architects, engineers, specialist designers and design development before and during construction. A build-only contractor with no qualifying design function or control cannot satisfy the Principal Designer test simply because it is the Principal Contractor on site.
Timing also counts. HSE says the Principal Designer should be appointed as early as possible in the design process and, where practicable, at concept stage. Where a contractor takes over design later, its appointment needs to match the part of the pre-construction phase it actually controls; putting its name against the role later does not rewrite who controlled earlier design work.
Design and build does not make the appointment automatic
A common assumption is that the Principal Contractor automatically becomes Principal Designer when the project uses a design-and-build contract. CDM does not say that.
On a commercial project, the client remains responsible for making the required appointments in writing. Regulation 5 requires both roles to be appointed; it does not require two separate appointment letters, so one properly drafted contract or appointment can identify the same organisation in both capacities.
The document should leave no doubt about the statutory roles being accepted and when each appointment starts. The company should also know who within its organisation is exercising design-phase control and who is managing construction, particularly where design continues after work starts on site.
Domestic projects have different default provisions. If a domestic client on a multi-contractor project does not make the appointments, Regulation 7 places the Principal Designer role with the designer in control of the pre-construction phase and the Principal Contractor role with the contractor in control of the construction phase. Those functions could fall to the same organisation if it satisfies both descriptions.
Competence has to cover both sides of the project
Regulation 8 prevents a designer or contractor from accepting an appointment unless it has the skills, knowledge and experience, and for an organisation the organisational capability, needed for the role. The person making the appointment must take reasonable steps to satisfy themselves that those conditions are met.
For the Principal Designer function, HSE expects evidence of relevant construction knowledge and the ability to understand, manage and coordinate the pre-construction phase, including significant and foreseeable risks managed through design. HSE gives CPD records, professional memberships and previous experience as examples of evidence, with SSIP assessment or the Common Assessment Standard among the possible evidence of organisational capability.
The Principal Contractor assessment has a different emphasis: construction-phase planning, coordination, site management and control of contractors. A contractor may have strong evidence for that role without automatically demonstrating the design-risk management capability needed for the Principal Designer appointment.
An SMSTS certificate, for example, may form part of a site manager's competence record. It does not by itself demonstrate that the organisation can control multidisciplinary design, coordinate pre-construction information or manage foreseeable risks through design decisions. A combined appointment needs evidence covering the whole scope.
What evidence should exist on a dual appointment?
The first record is the written appointment itself. The client should also be able to show how it assessed the organisation against both roles, because Regulation 8 places a duty on the person making an appointment to take reasonable steps to check capability.
On the Principal Designer side, the project record would normally show who controls the design process, how designers are coordinated, design-risk reviews, pre-construction information, decisions to eliminate or reduce foreseeable risks, residual risk information and communication with the construction team.
The Principal Contractor evidence should show construction-phase planning and control: the construction phase plan, coordination of contractors, site rules, inductions, worker consultation, welfare, access controls and records showing that changes in risk have been acted on during construction.
Where the same company holds both roles, the strongest record connects the two. A design risk identified before construction should be traceable through the design decision, information given to the site team and the control actually used when that work is built. The same applies to design changes made after construction starts.
Does holding both roles create a conflict?
CDM 2015 does not impose a general independence requirement between the Principal Designer and Principal Contractor. If Parliament had required the roles to be held by separate organisations, the regulations could have said so; HSE instead expressly recognises that one organisation may hold more than one dutyholder role.
There is still a management issue to deal with. Regulations 11 and 13 require the Principal Designer and Principal Contractor to liaise and exchange information. When both functions sit inside one company, the project record should still show that design-stage risks were identified and dealt with before or during the corresponding construction work.
A late design change is a good test. If changing a façade fixing, temporary support arrangement or access sequence affects construction risk, the organisation needs to perform both functions: assess the foreseeable risk through its design process and then manage the resulting work through its construction-phase controls. A single company name on both appointments is not evidence that either step happened.
CDM does not prescribe an internal organisational chart or require a separate 'Chinese wall' between the functions. On a large project, using identifiable design-management and construction-management responsibilities can make it much easier to demonstrate who made a decision, what information was reviewed and how it reached the people doing the work.
Do not confuse the CDM roles with Building Regulations roles
Projects in England may also have a Principal Designer and Principal Contractor under the Building Regulations 2010 dutyholder regime. They carry the same titles but have a different purpose: the Building Regulations roles deal with compliance of design and building work with the Building Regulations.
Government guidance confirms that the CDM Principal Designer and Principal Contractor can also carry out the corresponding Building Regulations roles. The client must confirm the appointments in writing, and the competence requirements for the Building Regulations functions still have to be met.
An appointment as CDM Principal Designer therefore does not automatically make the organisation the Building Regulations Principal Designer, and the same applies to the Principal Contractor. LCM's comparison of the CDM and Building Regulations Principal Designer roles explains where the two regimes separate.
Frequently asked questions
Can the same company be Principal Designer and Principal Contractor?
Yes. HSE confirms that one organisation can perform more than one CDM dutyholder role, provided it satisfies the legal requirements and has the capability required for each appointment.
Yes. HSE confirms that one organisation can perform more than one CDM dutyholder role, provided it satisfies the legal requirements and has the capability required for each appointment.
Does a design-and-build contractor automatically become Principal Designer?
No. The client must make the Principal Designer appointment in writing on a commercial multi-contractor project, and the contractor must be a designer with control over the pre-construction phase.
No. The client must make the Principal Designer appointment in writing on a commercial multi-contractor project, and the contractor must be a designer with control over the pre-construction phase.
Do the Principal Designer and Principal Contractor need separate appointment letters?
CDM requires the appointments to be in writing but does not prescribe two separate documents. One appointment or contract can identify the same organisation as holding both statutory roles.
CDM requires the appointments to be in writing but does not prescribe two separate documents. One appointment or contract can identify the same organisation as holding both statutory roles.
Can the same company also hold the Building Regulations roles?
Yes, in England the same organisation can hold the corresponding Building Regulations Principal Designer and Principal Contractor roles if the appointments are confirmed and the organisation meets the separate competence requirements.
Yes, in England the same organisation can hold the corresponding Building Regulations Principal Designer and Principal Contractor roles if the appointments are confirmed and the organisation meets the separate competence requirements.
For commercial projects involving more than one contractor, Regulation 5 requires the Principal Designer and Principal Contractor appointments to be made as soon as practicable and, in any event, before the construction phase begins. HSE advises appointing the Principal Designer as early as possible in the design process.
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