Contractor proof of insurance: what to ask for and how to verify it.

What counts as proof

Three document types are commonly presented, and they are not equal:

• Certificate of insurance (US: often an ACORD 25 form; UK: certificate of employer's liability insurance, or a broker-issued confirmation of cover). Issued by the insurer or broker, summarises the live policy. This is the standard.
• Policy schedule. The insurer's own statement of what the policy covers. Stronger than a certificate but longer, and contractors rarely carry it.
• A letter or email from the contractor themselves. Not proof. Self-declaration of cover has no evidential weight when a claim is challenged.

The five fields to check on every certificate

1. Insured party. The name on the certificate must match the firm doing the work. A certificate in the name of a parent company, a director personally, or a similarly named firm does not cover the entity on your site.
2. Policy type. Public liability (UK) or commercial general liability (US) for third-party damage; employer's liability (a legal requirement for UK employers) or workers' compensation (US) for the contractor's own staff; professional indemnity where the work involves design decisions.
3. Limits. Compare against your site's stated minimum, not against what looks big. A £2m public liability certificate at a site whose contractor policy requires £5m is a fail.
4. Expiry date. The date that matters is the date of the visit, not the date the document was collected. A certificate collected in January proves nothing about September.
5. Issuer. A named insurer or regulated broker, with contact details you could verify against. An issuer you cannot identify is a red flag on its own.

Verifying the document is genuine

Certificates are PDFs, and PDFs are editable. The claims that collapse worst are the ones where a certificate was on file and turned out to have been altered. Practical verification, in rising order of effort:

• Internal consistency. Policy numbers follow insurer formats; dates that fall on renewals mid-week, mismatched fonts, or limits that differ between pages are the common tells of an edited document.
• Issuer confirmation. For high-risk work or long engagements, confirm cover directly with the broker on the certificate. Brokers answer these requests routinely.
• Additional-insured or principal's clause. Where your contract requires it, check the certificate actually names your organisation, because the base policy alone may not respond to your claim.

Check at every entry, not once a year

Collection at onboarding answers whether the contractor was insured then. The question that matters is whether they are insured today, at the gate, before the work starts. Policies lapse mid-engagement, renew at lower limits, or get cancelled for non-payment, and the facility is the last to hear. The working pattern: hold the certificate and its expiry date in the system that runs the gate, block entry automatically when the date passes, and notify the contractor firm 30 days out so the renewal arrives before the block ever triggers. That enforcement design is covered in contractor insurance verification at the gate.

Related reading

• Contractor insurance verification at the gate
• Contractor site induction: what to cover and when it expires
• Contractor compliance feature deep-dive
• Visitor and contractor management for manufacturing sites

Make the expiry date the blocker, not a note in a folder.

Upload a certificate in your demo, set the site minimums, and watch entry stop the day the policy lapses.