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Subcontractor Compliance Checklist for UK Main Contractors

Updated May 2026 — Applies to construction projects in England, Scotland, Wales and Northern Ireland

Before a subcontractor sets foot on site, a main contractor needs to be satisfied that they are competent, adequately insured, and aware of their health and safety obligations. This checklist covers the core documents you should collect and verify, the legal basis for each requirement, and how long to retain records.

The core document checklist

• Public Liability Insurance — minimum £2 million, though most commercial contracts require £5 million or £10 million. Verify the policy is current, covers the type of work being carried out, and that the insured name matches the subcontractor entity.
• Employers Liability Insurance — legally required under the Employers' Liability (Compulsory Insurance) Act 1969 for any subcontractor with employees. Minimum £5 million. Confirm the certificate is current and issued by an authorised insurer.
• CSCS Cards — Construction Skills Certification Scheme cards confirm that workers hold relevant qualifications for their trade. Different card colours indicate different competency levels. Site managers should verify cards before workers begin.
• Method Statement (RAMS) — a written document explaining how specific tasks will be carried out safely. Required under the Management of Health and Safety at Work Regulations 1999 for activities with significant risk. Should be task-specific, not generic.
• Risk Assessment — identification of hazards, assessment of risk, and control measures. Required under the Management of Health and Safety at Work Regulations 1999. Should be reviewed and updated when working conditions change.
• Health & Safety Policy — required by law under the Health and Safety at Work Act 1974 for businesses with five or more employees. Should be signed, dated, and reviewed regularly.
• Gas Safe Registration — mandatory under the Gas Safety (Installation and Use) Regulations 1998 for any subcontractor working on gas appliances, fittings, or flues. Always verify registration directly on the Gas Safe Register website.
• Electrical Certification (NICEIC / NAPIT) — required for electrical installation work in most circumstances. Verify current registration status directly with the relevant scheme.
• CHAS or Constructionline Accreditation — pre-qualification schemes that confirm a subcontractor has been assessed for health and safety competence. Not a legal requirement, but increasingly specified by clients and frameworks.
• CIS Registration — Construction Industry Scheme registration confirms the subcontractor is correctly registered for tax purposes. HMRC provides a verification service. Failure to verify can result in tax liability for the main contractor.

Insurance — what to check beyond the headline figure

An insurance certificate that appears valid can still leave you exposed. When reviewing a subcontractor's certificate of insurance, check:

• The insured name matches the legal name of the subcontracting entity (not a trading name)
• The expiry date is after the expected completion of the subcontract
• The scope of cover includes the type of work being carried out
• The policy covers work away from the principal place of business
• Any exclusions that might apply to the specific project

How long to keep records

Retaining compliance documents matters as much as collecting them. In the event of an incident, enforcement action, or dispute, you may need to produce evidence that a subcontractor was adequately vetted at the time work was carried out.

• Accident-related documents: retain for at least 3 years (RIDDOR), but 12 years is advisable for serious incidents given personal injury limitation periods
• Insurance certificates: retain for at least 6 years after the policy period
• RAMS and risk assessments: retain for the duration of the project plus 3 years minimum
• Health and safety records generally: 3–6 years is common practice

The most common compliance failures

In practice, the documents that most frequently cause problems are:

• Expired insurance — policies lapse and subcontractors don't always notify their clients
• Generic RAMS — method statements copied from another project and not reviewed for the specific site
• Wrong CSCS card category — a worker carrying a card for one trade working in another
• Unverified accreditations — CHAS or Constructionline certificates that have since lapsed