🏗️ For Main Contractors & Principal Contractors

Require NAS-Certified Subcontractors
On Every Project You Deliver.

As principal contractor, you own the compliance of your entire supply chain under CDM Regulations. NAS gives you independently assessed, publicly verifiable subcontractor compliance — covering H&S, RIDDOR, Modern Slavery, Environmental Protection, and Procurement Act 2023 selection evidence — so you can build with confidence.

Free
Register Verification
22
Laws Covered at Gold
ISO 17021
Aligned Assessment
100%
Independent Review

Why Require NAS From Your Subcontractors?

Under CDM 2015, you are responsible for the health, safety, and legal compliance of every subcontractor on your site. A non-compliant subcontractor incident isn't just their problem — it is yours. Independent verification matters.

The Risk Without It

CDM 2015 (regulation 8) requires you to take reasonable steps to satisfy yourself that subcontractors have the skills, knowledge, and experience to carry out their work safely and compliantly
RIDDOR reportable incidents involving subcontractors without evidenced H&S compliance result in HSE investigation of the principal contractor
Modern Slavery Act non-compliance in your supply chain exposes your organisation to reputational and legal liability as the contracting body
Environmental Protection Act breaches by subcontractors on your site — illegal waste disposal, spillages — can trigger enforcement against you as site controller
On public projects tendered under the Procurement Act 2023, the buyer can ask about your subcontractors and exclude a bid if one of them meets an exclusion ground — self-declaration alone won't pass scrutiny
A non-compliant subcontractor on a live project can halt work, trigger client disputes, and damage your approved supplier status

Why Requiring NAS Protects You

NAS-certified subcontractors have independently evidenced H&S, RIDDOR, and Modern Slavery compliance — documented and verifiable by your teams, not just procurement
Each certificate is backed by documents an assessor has actually reviewed — insurance, RAMS, training records and policies — not a self-declared questionnaire
Search the free NAS register by name or certificate number to confirm tier, status and expiry before a subcontractor starts
NAS Gold covers the disclosures behind the Procurement Act 2023 exclusion grounds and environmental controls — useful evidence for public sector principal contractor work
Annual renewal means you're always looking at current compliance status, not a one-off registration snapshot — and lapsed certificates stop showing as current on the register

How NAS Works For You

Independent, evidence-based contractor certification you can rely on.

Instant Register Search

Verify any subcontractor free on the NAS public register — by name or certificate number, no login required. Confirm current NAS tier and certificate status before they step on site.

CDM-Ready Evidence

NAS certification provides independently reviewed, documented evidence of subcontractor compliance — helping you show the reasonable steps CDM 2015 (regulation 8) expects before you appoint a subcontractor.

Annual Re-Assessment

Certificates last a year and renewal means a fresh evidence review, so a current NAS certificate reflects documents checked within the last twelve months.

Verify a Contractor Right Now

Search the NAS public register to instantly confirm any contractor's current certification status and tier — free, no login required.

Frequently Asked Questions

Are You a Contractor? See Your Trade

PlumbersElectriciansRoofersBricklayersCarpenters & JoinersDrain ClearanceFitters & InstallersAll Trades

Raise Your Supply Chain Standard

Start requiring NAS certification from your contractors — independent, evidence-based, and publicly verifiable.

Related Pages

Procurement GuideHow Certification WorksAccredited RegisterGovernance & ImpartialityAll Sectors & Trades