If you bring contractors onto your site, the Health and Safety Executive expects you to manage them. That obligation does not live in a single regulation — it is spread across the Health and Safety at Work etc. Act 1974, the Management of Health and Safety at Work Regulations 1999, the Construction (Design and Management) Regulations 2015, and a body of HSE guidance documents. Together they describe a process: select competent contractors, inform them properly, coordinate the work, monitor performance, and review what happened.
This guide describes that process in practical terms — what HSE actually expects to see on a UK construction site, what evidence will satisfy an inspection, and where most contractor management failures originate.
Why contractor management matters under UK law
A client or principal contractor cannot delegate health and safety responsibility by hiring a contractor. The duty to ensure work is done safely sits with the duty holder regardless of who physically carries the work out. This principle runs through the regulations:
- Section 3 of the Health and Safety at Work etc. Act 1974 imposes a duty on employers to conduct their undertaking so as not to expose non-employees (including contractors) to risk so far as reasonably practicable.
- Regulation 11 of the Management of Health and Safety at Work Regulations 1999 requires employers and the self-employed who share a workplace to cooperate and coordinate health and safety arrangements.
- The Construction (Design and Management) Regulations 2015 add construction-specific duties — pre-construction information, principal contractor coordination, and the construction phase plan.
HSE's foundational guidance on the topic is HSG159 ("Managing contractors: a guide for employers"), which sets out a five-stage approach used across UK industries. For construction work, CDM 2015 layers project-specific requirements on top.
The five stages of HSE contractor management
HSE's contractor management framework, drawn from HSG159 and reinforced in subsequent guidance, follows a sequence of five stages. Each has a regulatory grounding and produces evidence that inspectors look for.
Stage 1 — Plan the work
Before you select a contractor, define what work needs doing and what the hazards are. This is the principal contractor's responsibility under CDM 2015 Regulation 13, drawing on pre-construction information from the client and principal designer under Regulation 4(4) and Regulation 11.
The plan should answer:
- What is the work? Define the scope precisely — vague specifications produce vague controls.
- Where will it happen, when, and over what duration?
- What hazards are present in the work itself, the environment it will be carried out in, and the interaction between the two?
- What competencies does the contractor need to do this work safely?
- What information must the contractor have before starting?
This stage is what the construction phase plan documents. For non-construction contractor work (maintenance, cleaning, IT installation), the equivalent output is a written method statement and risk assessment tied to a permit-to-work.
Stage 2 — Select a competent contractor
Competence is a defined regulatory concept under CDM 2015 Regulation 8(1):
"A designer (including a principal designer) or contractor (including a principal contractor) appointed to work on a project must have the skills, knowledge and experience, and, if they are an organisation, the organisational capability, necessary to fulfil the role that they are appointed to undertake, in a manner that secures the health and safety of any person affected by the project."
Selecting a competent contractor means demonstrating, before appointment, that they have:
- The technical skills to do the trade.
- Knowledge of the relevant health and safety regulations.
- Experience of similar work in similar environments.
- The organisational systems to manage their own workers and their own subcontractors.
In practice this is evidenced through prequalification — typically a contractor prequalification questionnaire (PQQ) covering insurance, accreditations, references, recent incident history, and management arrangements. See our PQQ guide and free template for the detailed structure.
For construction work above certain thresholds, third-party accreditation schemes recognised under the Common Assessment Standard (CAS) developed by Build UK are commonly used. Worth noting: PAS 91, the older prequalification standard previously published by BSI, is no longer maintained — Build UK's CAS is now the dominant prequalification framework. See our PQQ guide for the full sectional structure of a current PQQ.
Stage 3 — Provide information and instruction
Section 3 of the Health and Safety at Work Act and Regulation 11 of the Management Regulations both require employers to share relevant health and safety information with contractors who will work in their premises or alongside their employees.
For construction projects this is operationalised through:
- Pre-construction information (CDM 2015 Regulation 4(4) and Regulation 11) — the package the client and principal designer compile before contractors are appointed, covering known hazards on the site, the design constraints, and any residual risks from earlier phases.
- Site induction — every worker arriving on site is briefed on the site rules, emergency arrangements, welfare facilities, and the specific hazards relevant to their work.
- Toolbox talks — short, focused briefings on specific issues as they arise (a new hazard, a near-miss, a seasonal risk).
Evidence: induction attendance records, signed acknowledgements of site rules, toolbox talk attendance sheets. HSE inspectors routinely ask to see these.
Stage 4 — Coordinate and monitor the work
This is the principal contractor's coordinating duty under CDM 2015 Regulation 13 — to "plan, manage, monitor and coordinate" the construction phase, ensuring that the activities of different contractors do not create conflicting hazards.
Practical coordination includes:
- Pre-start meetings with each new contractor confirming their RAMS, permits, and welfare arrangements.
- Daily or weekly progress meetings where overlapping work is reviewed.
- Permit-to-work systems for high-risk activities (hot works, confined spaces, work at height above 4 metres, work near live services).
- Active monitoring — inspections, observations, audits — not just reactive monitoring of incidents.
Monitoring should be documented. A logbook of site visits, inspection findings, and corrective actions taken serves both as a management tool and as evidence in the event of an incident or inspection.
Stage 5 — Review performance
After the work is complete (or at regular intervals on longer projects), review what happened. What worked? What near-misses or incidents occurred? What would you do differently next time?
For contractor management specifically, the review should also feed back into the prequalification process — a contractor who performed poorly should be flagged, and serious failures may justify removal from the approved list.
What HSE inspectors look for
When an HSE inspector visits a construction site, contractor management is one of the standard areas they probe. The most common questions:
- Who is the principal contractor, and were they appointed in writing? (Regulation 5)
- Where is the current construction phase plan? Has it been updated recently?
- Show me the induction records for the contractors currently on site.
- How do you check that contractors have the competence required for the work they are doing?
- What is your permit-to-work system for [specific high-risk activity]? Show me a current example.
- Who is responsible for monitoring the contractors' work? When were they last on site? What did they find?
Inability to answer these promptly, with documentation, is a flag. HSE's enforcement decisions repeatedly cite breakdowns in contractor management as contributory factors in serious incidents.
Common contractor management failures
The patterns are predictable:
- Selection without verification. Contractor produces an old certificate, the principal contractor files it without checking whether the insurance is current or the accreditation has been renewed. By the time the work is underway, the documentation is expired.
- Information that does not reach the workforce. PCI exists, construction phase plan exists, but the contractor's workers were never inducted properly. They turn up not knowing the site rules, the emergency arrangements, or the specific hazards in their work area.
- Coordination by email. No pre-start meeting, no documented handover, no shared programme showing which contractors are working where and when. Conflicting work happens because no one realised it would.
- Monitoring as an afterthought. Site visits when something goes wrong rather than as a planned routine. By the time a problem is visible, the work has already happened.
- No closeout. Project ends, contractor leaves, no review of how they performed. Same contractor is re-engaged on the next project with no record of how the previous one went.
How software supports HSE contractor management
The five-stage framework is built around information flowing reliably between client, principal contractor, contractors, and their workforce. Where that information lives on paper, in email chains, and in someone's head, it tends to drift.
Subcontractor compliance software supports the stages that depend on current, verifiable information:
- Selection (Stage 2): a single record of each contractor's insurance, accreditations, CSCS cards, and prequalification status, with expiry alerts so cover does not lapse unnoticed.
- Information (Stage 3): induction records and site rule acknowledgements stored against the worker, accessible to the supervisor before they sign off the worker as inducted.
- Coordination (Stage 4): a current view of which subcontractors are active, what their compliance status is, and what evidence supports their continued presence on site.
- Review (Stage 5): a history of compliance events, near-misses, and document expiries that feeds the closeout review.
For a deeper look at the software category, see our subcontractor management software guide and contractor management systems guide.
SubComply is being built specifically for UK principal contractors managing the contractor-management workflow described in this guide. Join the waitlist to be notified when it launches.
Where this guide stops
This guide covers the regulatory framework, the five stages, and the practical evidence inspectors look for. What it does not do is replace project-specific advice: every site has its own combination of work, hazards, and people, and the controls that work on one will not necessarily work on another. Use this as the framework, then build the project-specific detail on top.
For the document that ties contractor management together on a construction project, see our construction phase plan guide. For the broader CDM compliance context, see our CDM compliance guide.