How to get on main contractor supply chains and frameworks
How main contractors build their supply chains, which frameworks matter, what procurement teams check before they add a subcontractor and seven steps to get on the list.
- Main contractors buy from an approved register, and the register is filled by procurement teams who search Google, the Constructionline and CHAS registers and, increasingly, AI assistants.
- Public work comes through frameworks such as SCAPE, Pagabo, Procure Partnerships and the regional frameworks, and their standards flow down to you as PQQ questions and website checks.
- The seven things checked before you are added can all be answered on a website: accreditations written out, insurance limits, ISO certificates, consistent business details, case studies at value, H&S figures and a tender contact.
- One accreditations page with every certificate written out and linked to its register is the single change that moves a firm from “cannot verify” to “approved”.
- Follow up through the site team you already know; your website is what procurement opens when they ask.
Most subcontractors get onto a main contractor’s supply chain one of two ways: someone on site vouched for them, or a buyer went looking and found them. The first route is slow and depends on luck. The second depends on whether the buyer could find you, verify you and put you forward without a phone call. This guide is about the second route, because it is the one you control.
How a main contractor actually builds a supply chain
A Tier 1 or regional main contractor keeps a register of approved subcontractors. Getting on it means passing a pre-qualification check: SSIP accreditation, insurance limits, financial standing, health and safety record, relevant experience and, increasingly, environmental and social value evidence. Once you are on it, you get invited to tender for packages that match your trade and the values you have delivered at before.
The register is run by a procurement team or a supply chain manager, not by the site team you know. When a bid comes in, they look at the trades they need, search the register, and if there is a gap they go looking. They search Google, they check Constructionline, and in 2026 a growing number ask an AI assistant to shortlist firms by trade and region. If your website gives them nothing to verify, you are not on the list they send to the estimator.
The frameworks that matter
Public sector work in the UK is bought mostly through frameworks: pre-tendered agreements that let a council, NHS trust, housing association or university appoint a contractor without a full procurement each time. The ones subcontractors run into most are SCAPE, Pagabo, Procure Partnerships, Fusion21 and Crown Commercial Service nationally, with regional frameworks such as NEPO in the North East, YORhub in Yorkshire, the North West Construction Hub, SEWSCAP in South Wales and the hub companies in Scotland.
You do not usually tender for a framework directly. The main contractor holds the framework place and brings its supply chain with it. What a framework does is set the standard the main contractor has to prove about that supply chain: accreditations, local employment, social value, carbon reporting. Those standards flow down to you as questions on a PQQ and as checks on your website. Our framework calendar shows where each of the major frameworks is in its cycle, so you know when a contractor’s supply chain is about to be built or refreshed.
What a procurement team checks before it adds you
- SSIP accreditation, meaning CHAS, Constructionline, SafeContractor or SMAS, with the level and expiry date, confirmed on the register rather than on your logo strip.
- Insurance: public liability, employers’ liability, contract works and professional indemnity where you design, with the limits stated.
- ISO 9001, 14001 and 45001 where you hold them, with the certification body and scope.
- Financial standing: Companies House filings, turnover and whether your business details match across the registers.
- Experience at their value band: case studies with the client, the main contractor, the package value, the programme and the sector.
- Health and safety record: accident frequency rate, RIDDOR history, a named H&S lead.
- A contact who deals with tenders, and evidence you respond within a working day.
Every one of these can be answered on a website before anyone emails you. Most subcontractor sites answer almost none of them: our October 2026 audit of seventeen North East subcontractor websites found only one that stated an accreditation level or expiry date, and none that gave a health and safety figure. The free Tender Check scores exactly these things.
Seven steps to get onto the supply chain
- Decide which contractors and frameworks you want. Pick three main contractors active in your region and the sectors you want more of, and find out which frameworks they hold. Their websites and the framework operators’ websites list it.
- Get your accreditations in order and written out. One accreditations page on your site, with every certificate, level, issuing body and expiry, each linked to the public register. This is the single change that moves a firm from “cannot verify” to “approved”.
- Match your business details everywhere. Company name, registered number, address and phone identical on your website, Companies House, Constructionline, CHAS and Google Business Profile. Procurement teams and AI tools both compare them.
- Write three case studies the way a PQQ asks for them. Client, main contractor, sector, value band, programme, scope and a named contracts manager. Not a gallery with a caption.
- Produce a capability statement. Two pages, built from your website so it never goes out of date, with your trades, accreditations, sectors, values and contacts. Buyers attach it to a tender.
- Register on the contractor’s supply chain portal. Most Tier 1s run one, often through Constructionline, Achilles or their own system. Use the same details and the same evidence as your website, so the two agree.
- Follow up through the site team, not the procurement team. Once your registration is in, the contracts manager you already know can ask procurement to pull it through. Your website is what procurement opens when they do.
Why the website carries so much of this
A supply chain manager does not have time to email forty subcontractors for certificates. They open the website, and if the accreditations are written out and linked, the case studies answer the quality question and there is a named tender contact, you go on the list. If the accreditations are logos, every trade shares one page and the contact is an info@ address, you do not, however good the work is.
The same is now true of AI tools. Ask ChatGPT or Google AI which groundworks subcontractors in your region have worked for a Tier 1 and it names the firms whose sites give it something to verify. It cannot read a logo. It can read “CHAS Advanced, expires March 2027” and a case study with a value band.
What to do this week
- Run the free Tender Check on your own site. It takes three minutes and scores the sixteen things a procurement team checks.
- List the three main contractors you most want work from and find out which frameworks they hold.
- Open your accreditations page, if you have one, and count how many certificates are written out with an expiry date. If the answer is none, that is the first fix.
What changed in 2025 and 2026
Two things have moved since most subcontractor websites were last rewritten. The first is pre-qualification. PAS 91 was withdrawn in 2023 and the Common Assessment Standard, developed by Build UK, has replaced it as the question set main contractors and public bodies pre-qualify against. Procurement Policy Note 03/24 tells public sector buyers to use it for works contracts, and Build UK reported more than 21,000 suppliers certified by July 2025, when building safety questions became mandatory for anyone working under the Building Safety Act.
Anyone carrying out work under the Building Safety Act should make sure they have the Common Assessment Standard.
Jo Fautley, deputy chief executive, Build UK, July 2025
The second is the Procurement Act 2023, in force for new public procurements since 24 February 2025. It implies 30-day payment terms into public contracts and, under section 73, into the subcontracts beneath them; it lets frameworks reopen to new entrants during their life; and from 1 April 2026 it moved notices onto the Central Digital Platform with quarterly publication of payment performance. For a subcontractor that means the supply chain is more open than it was, and the evidence buyers expect is more standardised. A website that states your Common Assessment Standard certification, your Constructionline level and your payment terms is answering the questions the new regime asks.
Constructionline itself reports around 10,000 buyers from 3,800 organisations using its register, and its Gold membership, which carries the Common Assessment Standard, is the level VINCI, Wates, BAM, Kier and Balfour Beatty ask their supply chains to hold. It is also the level AI assistants can find when they look you up, which is why the accreditations guide treats the register entry and the website as one piece of evidence.
Questions this raises
Do I need to be on Constructionline to work for a Tier 1?
Not always, but most Tier 1s and many regional contractors use it as their first filter and ask for Gold. If you tender for public sector or framework work it is close to essential, and the Gold questions mirror what a PQQ asks anyway.
How long does it take to get onto a supply chain?
With your evidence in order, registration on a contractor’s portal typically takes two to six weeks to be approved. The slow part is usually gathering the evidence, which is why having it on your website already saves months.
Can a small firm get onto a Tier 1 supply chain?
Yes, if the accreditations, insurance and experience match the package value. Tier 1s need ten-person specialists as much as they need large firms. What stops small firms is evidence they cannot produce quickly, not size.
Will a framework pay me directly?
No. The main contractor holds the framework place and contracts with you as a subcontractor. The framework sets the standards; the main contractor applies them to you.
See where your own website stands.
The free Tender Check scores your site on the four stages buyers and AI tools check before they shortlist a subcontractor. Three minutes, your result straight away and a personal review within one working day.
