Appointing a subcontractor does not transfer away the principal contractor’s duty to plan, manage, monitor and coordinate the construction phase. Subcontractors retain responsibility for work under their control, but the principal contractor still needs to check competence, coordinate activities, maintain suitable site arrangements and intervene where unsafe work is foreseeable or observed.
A serious fall shows where contractor control can fail
In July 2026, the Health and Safety Executive reported the prosecution of a principal contractor after a labour-only subcontractor suffered life-changing injuries while dismantling pipework.
A scissor lift had been ordered but could not access the work area. Instead of stopping and selecting suitable access equipment, a forklift truck and tipping bucket were used. HSE found there were no suitable arrangements for managing contractors, no adequate supervision and no effective system preventing untrained people from accessing the equipment.
The lesson goes beyond the particular equipment involved. When the planned method becomes impracticable, the work should be reassessed. An improvised alternative should not become the new method simply because the job is already under way.
What must a principal contractor legally do?
Under the Construction (Design and Management) Regulations 2015, a principal contractor on a project involving more than one contractor must plan, manage, monitor and coordinate health and safety during the construction phase.
That includes organising cooperation between contractors, coordinating work where activities interact, maintaining the construction phase plan, providing suitable site inductions and ensuring workers receive the information, instruction, training and supervision they require.
Contractors retain duties of their own. They must plan, manage and monitor the work under their control and cooperate with the principal contractor. The duties deliberately overlap: the principal contractor coordinates the project while each contractor controls its own operation.
Does approving RAMS transfer responsibility?
No. A principal contractor’s review of subcontractor RAMS does not make the principal contractor the author of every specialist method. Equally, accepting a document does not remove the responsibility to consider whether the method is suitable for the actual project.
A meaningful review should ask whether the RAMS describe the real scope and location, whether the proposed equipment will physically fit, whether interactions with other trades have been considered, what competence and supervision are required, and what should happen if site conditions or the planned method change.
Where work materially departs from the agreed method, our professional recommendation is to stop, reassess and obtain fresh authorisation before continuing.
Who controls labour-only subcontractors?
The expression “labour-only subcontractor” can cover different contractual arrangements. From a site-safety perspective, the important questions are practical: who controls the work, who provides the equipment, who gives instructions, who appoints the supervisor and who has authority to stop the activity?
Before work begins, the parties should agree who provides task-specific supervision, who verifies training and authorisation, who controls access to plant and equipment, who approves changes to the method and who coordinates with other contractors.
A labour-only arrangement should never create a gap where the principal contractor assumes the subcontractor is supervising the workers while the subcontractor assumes the principal contractor is directing them.
Improvised access equipment should be a warning sign
A tipping bucket is not a purpose-designed working platform. HSE’s guidance on working platforms used with forklift trucks explains that forklift trucks are primarily intended to lift materials rather than people. Even a properly designed non-integrated working platform should only be used in exceptional circumstances and under controlled conditions.
If a MEWP, scaffold or planned access system cannot be used, that does not justify using the nearest available substitute. It should trigger a review of the work sequence, access constraints, equipment selection, obstructions and programme.
What should you do now?
- Define who controls each contractor and labour-only team.
- Check competence and organisational capability before appointment.
- Review RAMS against the actual site conditions.
- Confirm access equipment is suitable and will physically fit.
- Restrict equipment use to trained and authorised people.
- Identify high-risk stages requiring additional supervision.
- Monitor whether the agreed method is being followed.
- Stop work when equipment, conditions or sequencing change.
- Record significant interventions and corrective actions.
- Review contractor performance before future appointments.
Our professional view
A principal contractor does not need to stand over every subcontractor throughout every task. It does need a defensible system showing that contractors were selected carefully, given suitable information, coordinated, monitored and challenged where necessary.
The most revealing moment is often when the original plan stops working. A competent team pauses and finds a safe alternative. A weak system allows an improvised method to become the new plan without anyone formally deciding whether it is acceptable.
All Star Safety’s health and safety consultancy service includes RAMS reviews, site inspections and support with contractor-management arrangements. Managers and supervisors can also develop their risk-management skills through our IOSH courses and workplace-based Supervisory and Management NVQs.