CIS, Umbrella Companies and the Intermediaries Rules in Construction

Few areas of CIS generate as much practical risk as the use of intermediaries and umbrella companies in the construction supply chain. A principal contractor that engages workers through an intermediary, an agency, or an umbrella company is not just dealing with CIS, it is dealing with PAYE, the agency rules, the off-payroll working rules, the Managed Service Company legislation, and supply-chain liability provisions that can land unpaid tax back on businesses that thought they had transferred the obligation.

Before a contractor relies on an intermediary chain, the first question is whether the arrangement is genuinely compliant or just moving PAYE and CIS risk out of sight. That question becomes more urgent where the chain is financially weak: if a contractor later fails, the recovery issues covered in reclaiming CIS deductions after insolvency can arise alongside return and penalty problems such as appealing CIS monthly return penalties.

Why intermediaries and umbrellas are used at all

The construction sector relies heavily on temporary, project-based labour, and intermediaries and umbrella companies exist to absorb the administrative cost of engaging it. An agency supplies workers and handles their engagement; an umbrella employs the worker and contracts with the agency or end-client; a personal service company or labour-only subcontractor sits between the worker and the chain. Used properly, these structures are legitimate and widely accepted by HMRC.

The risk is not the existence of these structures, but the way they are sometimes used to obscure the true employment relationship, suppress employer NIC, or strip out PAYE that should have been operated. Legislation has been built up to address those abuses, and enforcement follows.

The agency rules in ITEPA 2003 Chapter 7

The agency rules at Chapter 7 of Part 2 of the Income Tax (Earnings and Pensions) Act 2003 treat certain workers supplied through an agency or other intermediary as employees of the agency for income tax and Class 1 national insurance purposes. The rules apply, broadly, where the worker personally provides services to a client through a third party, the worker is subject to (or to a right of) supervision, direction, or control as to the manner of the work, and remuneration is paid to the worker for the services.

Where the rules bite, the agency must operate PAYE and Class 1 NIC on the payments to the worker. The exception that previously allowed agencies to pay workers gross outside PAYE on the basis that they were self-employed has been substantially narrowed, particularly for construction. In practice this means a labour-only intermediary supplying construction workers will usually fall inside PAYE under Chapter 7 unless the supply genuinely sits outside the scope, which is a fact-specific judgement that should not be made informally.

What changes inside CIS

CIS still applies to construction operations, but a worker who is treated as an employee of the agency under Chapter 7 is not a subcontractor for CIS purposes in respect of that engagement. The payment becomes employment income, taxed under PAYE, and the CIS deduction does not arise on it. The agency, not the principal contractor, carries the PAYE obligation. Where the agency rules are misapplied or ignored, however, the unpaid PAYE can be pursued from other parties in the chain under transfer-of-debt provisions.

Interaction with off-payroll working (IR35)

The off-payroll working rules, often called IR35, apply where an individual provides services through their own intermediary (typically a personal service company) to a client. The 2017 public-sector reform and the 2021 private-sector reform shifted the responsibility for determining status from the individual's own company to the end-client (for medium and large clients) or to the fee-payer in the chain. Construction sits squarely within these rules where workers are supplied through personal service companies, and the typical project structure means an end-client and several fee-payers can sit between the worker and the principal contractor.

The interaction with CIS is layered: where a worker is inside IR35 the fee-payer must operate PAYE on the deemed direct payment, and CIS does not bite on that part of the chain because the income is employment income, not a subcontractor payment for construction operations. Where the worker is outside IR35 and CIS otherwise applies, the CIS deduction continues to be taken on the labour element of the payment in the usual way. The status determination statement (SDS) issued by the client is the document that governs which set of rules applies, and it has to be issued and passed down the chain correctly for the protection it offers to operate.

Managed Service Company legislation

The Managed Service Company rules at Chapter 9 of Part 2 of ITEPA 2003 catch arrangements where a worker is paid through an intermediary, but the intermediary is genuinely controlled by an MSC provider rather than the worker. The consequences are punitive: all payments through the chain are recharacterised as PAYE income of the worker, the unpaid tax can be recovered from the worker, the intermediary, and the MSC provider including its directors personally. HMRC has been increasingly active on MSC arrangements since 2022, with reported recoveries running into many millions in some cases.

For construction, the risk areas are workforce arrangements that look like umbrella employment but are structured to deliver the commercial benefits of self-employment to the worker, often via complex profit-share or loan-based remuneration. Any structure that pays the worker through a route that does not look like normal PAYE employment income should be specifically reviewed against the MSC rules.

Joint and several liability for unpaid tax in supply chains

A growing strand of UK tax legislation creates joint and several liability for unpaid tax in supply chains. For VAT, joint and several liability provisions allow HMRC to pursue a customer for the VAT that the supplier failed to pay where the customer knew or should have known the supplier was defaulting. For VAT registration, missing trader fraud rules apply similar logic in commodity supply chains.

Emerging legislation extends a comparable principle to PAYE in labour supply chains. The policy intent is to give HMRC a mechanism to recover unpaid PAYE from end-clients and fee-payers who used a non-compliant umbrella or intermediary, on the basis that the user of the labour supply chain had the practical ability to assess and control its compliance. The detail of these rules has shifted between consultation and implementation, and any business engaging workers through a multi-layered chain should track the position and document the due diligence it carries out on its supply chain.

Fraud risks in construction labour chains

Construction labour chains have historically been a target for fraud schemes. Mini umbrella company fraud, where umbrella structures are deliberately fragmented to abuse the employment allowance and the VAT flat rate scheme, has been a sustained HMRC enforcement focus. Disguised remuneration schemes routing payments through offshore entities or loan arrangements continue to surface despite the loan charge legislation. Phoenixing, where a company is liquidated with PAYE or VAT debts and replaced by a similar entity, is a recurring pattern in the lower end of the market.

The risk for a principal contractor is reputational and financial: even where the contractor is not directly party to the fraud, association with a non-compliant chain can attract HMRC scrutiny, supply-chain liability, and pressure from lenders, insurers, and customers who expect tax compliance to be visible. Reasonable diligence on intermediaries is, in this environment, part of the cost of doing business.

Red flags to watch for in an intermediary

A short list of patterns that should prompt deeper review before, or during, an engagement.

• Worker rates that appear to deliver a take-home pay above what mainstream PAYE could fund, with no obvious explanation.
• Remuneration described in unusual ways, including loans, profit-share, or payments routed offshore.
• A short trading history or recently incorporated intermediary handling large volumes of labour.
• Reluctance to share VAT registration, CIS registration, or PAYE references on request.
• An umbrella that operates outside any recognised accreditation scheme without a clear reason.
• Pricing that undercuts mainstream PAYE umbrellas by more than the modest margin reasonable competition allows.

None of these is conclusive on its own. Several together, or any single one without a credible explanation, should be treated as a reason to pause the engagement and seek specialist review.

Who carries which obligation

The combined effect of the rules above is that the same labour supply can carry different obligations at different points in the chain. The table sets out the typical pattern for a worker supplied through an umbrella to an agency to a principal contractor.

The pattern shifts where the chain involves a personal service company, an unincorporated agency, or an offshore element. The general point is that each party has a primary obligation and a backstop exposure, and the protections that allow a party to rely on the next link in the chain depend on documentation and on the chain itself being compliant.

A practical due diligence checklist

A defensible position on supply-chain compliance has to be evidenced. The checklist below is what specialist advisers typically work through on a new intermediary engagement.

1. 1Obtain and verify VAT, PAYE, and CIS registrations of every intermediary in the chain.
2. 2Review the intermediary's accreditation under any recognised industry scheme.
3. 3Sample the worker engagement documents and pay records to confirm PAYE is being operated on the gross pay.
4. 4Confirm the intermediary's status as a UK employer with proper banking arrangements.
5. 5Run periodic credit checks and adverse media searches on the intermediary.
6. 6Retain the evidence of each step with a dated note, so the file shows when each check was made.
7. 7Re-test the chain whenever a new intermediary is added or the legislation changes.

How HMRC views legitimate structures

Mainstream umbrella employment and properly run agency supply are legitimate ways to engage construction labour, and HMRC publicly recognises that. The issue is not the use of an umbrella, it is the use of an umbrella that is not actually operating PAYE on the worker's real gross pay, or that is structured to suppress employer NIC. The same point applies to off-payroll working: a worker properly inside or outside IR35, with a status determination statement issued and acted on at the right level of the chain, is the situation the rules are designed for. The risk arises where determinations are not made, are not passed down, or are made on a basis that does not survive review.

Common questions

Are agency workers in construction always inside PAYE?

Most labour-only agency supply for construction will engage Chapter 7 and therefore PAYE, because the supervision, direction, or control test is usually met on a construction site. Genuine subcontract arrangements where the worker is independent of agency control and supplies services on their own account can still fall outside, but the boundary is narrow and HMRC tests it actively.

Can we rely on the umbrella to handle compliance?

Operationally, yes; legally, only to the extent the chain itself is compliant and the due diligence supports it. Emerging supply-chain liability provisions mean the user of a non-compliant chain can be pursued for the unpaid tax, even where the umbrella was the failing party. Reliance has to be evidenced.

Does CIS still apply if the worker is inside IR35?

Where a worker is inside IR35 the fee-payer operates PAYE on the deemed direct payment and CIS does not bite on that part of the chain, because the payment is treated as employment income, not a subcontractor payment for construction operations.

What if we discover a problem in our supply chain?

Engage proactively. Stop new engagements through the affected route, review the historical exposure, take specialist advice on disclosure, and document the steps taken. HMRC treats engaged disclosure more favourably than discovery after the fact.