Approval checks when a subcontractor is replaced

A named subcontractor is approved for a project, then a different firm or crew arrives. The replacement may be capable, but the earlier decision was made about particular people, evidence and work arrangements. Copying the old “approved” status to the new party creates a gap at the exact point when site teams need a clear answer.

This guide covers a substitution **after** an initial approval. It is narrower than routine subcontractor prequalification. The HSE's Using contractors guide stresses identifying the job, making proportionate enquiries about a contractor's competence, sharing risks and coordinating work. Those questions need reconsideration when the contractor doing the work changes.

Capture what is changing

Record the original approved party, proposed replacement, reason for substitution, affected tasks, dates and decision owner. Confirm whether only individual workers are changing, a subcontracting firm is changing, or the method and equipment are changing as well. These cases need different checks. A worker swap under the same competent supervisor may be straightforward; a new specialist firm taking over lifting or electrical work is a material change.

Do not assume that a relationship between the two businesses transfers insurance, qualifications or responsibility. Identify the contracting chain and who will supervise the replacement on site. If the main contractor is arranging the substitution, it should explain how it has assessed the new party and what it will monitor.

Recheck the evidence that belonged to the original party

Match the replacement to the work: relevant skills, experience, training, authorisations, equipment and capacity. Check the correct legal entity and any contract-specific accreditation or insurance requirement. Confirm that the evidence is current and applies to the scope, rather than simply locating documents in a shared folder. Where the work needs specialist licensing or a competent technical sign-off, use the appropriate expert and official register.

Review whether the replacement has been briefed on site hazards, occupied areas, services, emergency arrangements and other contractors. A pass on a different site cannot prove readiness here. If documents are missing, state what can and cannot start while they are obtained. Do not use a generic “approved contractor” label to hide a restricted or temporary decision.

Review the method and interfaces

The original RAMS may name a supervisor, crew, equipment or sequence that no longer applies. Ask the replacement to adopt or revise the method through a controlled decision, and have the person responsible for the work review it before start. A new firm should not be asked to sign somebody else's document without understanding and accepting the method. If the task itself has changed, treat it as a scope change as well as a substitution.

Check permits, lifting plans, temporary works arrangements and handovers with the outgoing team. Identify incomplete work and any temporary controls left in place. The person taking over needs to know the current condition, not merely the planned condition described in a document from last week.

Issue a fresh, limited decision

Use a decision record that names the replacement, work package, site, evidence reviewed, restrictions and approver. State whether the substitution is accepted, pending specified evidence or rejected. Send the outcome to the main contractor, site contact, permit issuer and access-control team as applicable. Remove or amend the outgoing party's access deliberately; a new approval should not leave the old passes active by default.

Brief the replacement crew and confirm that the supervisor can explain the critical controls. Keep the prior approval and the new decision linked, so an investigator can tell which party was authorised on a given date. Review early performance where risk justifies it. A paper handover is not enough if actual work differs from the agreed method.

Learn from recurring substitutions

Frequent last-minute substitutions may reveal a planning or procurement problem. Record whether changes are caused by capacity, failed checks, scheduling or scope drift. Improve the contract's notice and approval route so a site is not forced to choose between a blind approval and an avoidable delay.

For a software comparison, see Complys contractor management software and ask to see how the current product distinguishes the old and new firm, their documents and the task-specific human decision. No software status should be treated as a transfer of competence from one legal entity to another.

Example: a specialist crew is swapped at short notice

An approved electrical subcontractor cannot attend and offers a sister company for the same shift. The project lead checks the new legal entity, supervisor, competence evidence and relevant insurance rather than transferring the first firm's badge. The method names the old supervisor, so the replacement confirms its own sequence and briefs the crew. The site contact checks whether permits, isolation ownership and interfaces with other trades change. The new approval is limited to the named work and date, and access for the original firm is adjusted. If the replacement cannot provide the needed evidence before the task begins, the site records what is held and why. This decision may be inconvenient, but it is clearer than discovering later that no one knew which company actually performed the work.

What not to copy from the old approval

Do not carry forward a training record, licence, insurer or technical method merely because the firms share a brand. Keep the original evidence for the work the first party did, and attach the new party's evidence to the period and scope it actually covers. A future reviewer should see the substitution date without needing to infer it from invoice names.