Free downloads · Free checklist · for principal contractors
Ask for this before the gang starts
Every principal contractor asks a new subcontractor for paperwork — hardly anyone does it the same way twice. This checklist turns it into a fixed process: what you ask for at the start, what you refresh every quarter, and a sample email to request the whole pack in one go.
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The four blocks on the page
- Company — Companies House details and UTR, CIS verification before the first payment, employers' and public liability insurance, SSIP accreditation and right-to-work assurance.
- Per worker on the gang — identity recorded for the site register, CSCS card checked with Smart Check, role-specific tickets with expiry dates, first aid cover and the site induction.
- Agreements in writing — the subcontract with documentation and training requirements set out, RAMS approved before the start, CIS payment terms and the site rules acknowledged.
- Repeat every quarter — a Smart Check spot-check on cards, insurance and SSIP expiry dates, and CIS re-verification where needed.
- Sample email — a short, businesslike email requesting the complete pack — copy and send.
Asking once isn't enough
The onboarding moment is the easy part: the subcontractor wants the job and delivers neatly. The risk sits in the months that follow — cards expire right through your programme, and an insurance certificate from January says nothing in October.
That's why the page carries a quarterly rhythm next to the onboarding. What was valid at the start can have expired next month; whoever finds that out at an audit or after an accident doesn't have a file, they have a problem.
Frequently asked questions
What documents should I ask a new subcontractor for?
As a minimum: company details and UTR so you can verify them with HMRC under CIS before the first payment, current employers' liability (legally £5m minimum) and public liability insurance certificates, SSIP accreditation such as CHAS, Constructionline or SafeContractor (or a completed health and safety questionnaire), approved RAMS for the package, and per worker the CSCS card and any role-specific tickets with their expiry dates. Ask for written confirmation that right-to-work checks have been done for everyone on the gang.
How often do I need to re-verify a subcontractor under CIS?
You must verify a subcontractor with HMRC before you first pay them, and again if you haven't included them on a CIS return in the current or the two previous tax years. Verification tells you the deduction rate — gross, 20% or 30% — and paying at the wrong rate is your liability, not theirs.
Can I rely on the subcontractor's own right-to-work checks?
The statutory duty sits with the employer, so the subcontractor carries the civil penalty — up to £60,000 per illegal worker since February 2024 — for their own staff. But a principal contractor that knowingly lets illegal working happen on its site is exposed too, and clients increasingly ask you to evidence your supply chain. Get written assurance and record, per worker, the identity document type and number for the site register; don't keep copies you don't need.
Further reading
- CSCS Smart Check at the gate: how the check works
- The site requirements matrix (Excel) — the gate check for your whole gang
- Certly for construction: cards, tickets and subcontractors in one place
Rather have this happen by itself?
Certly tracks certificates, inspections and licences automatically: reminders at 90, 60 and 30 days, escalation at 14 and 7, and an evidence pack at the press of a button. Trying it costs nothing.