Do Main Contractors Have to Check Subcontractors' Right to Work? (October 2026 Rules)

2026-10-19

Yes. Since 1 October 2026 a main contractor can be treated as the employer of anyone who personally carries out work through its subcontract chain, and can be fined up to £60,000 per illegal worker unless it put three things in place before the work started: written contract terms, substitution controls and identity verification. The subcontractor who engages each worker still has to carry out the right to work check itself.

In short

The Border Security, Asylum and Immigration Act 2025 extended the Right to Work Scheme beyond direct employees to individual sub-contractors and other working arrangements.

Under the new "extended liability" rules, a construction company that delivers work through a chain of subcontractors can be held liable for illegal working anywhere in that chain.

Your defence is a statutory excuse: contract terms, substitution controls and identity verification, all in place before work starts, with evidence that they actually operate.

Civil penalties are up to £60,000 per illegal worker. Knowingly employing an illegal worker is a criminal offence carrying up to five years in prison.

This guide is based on the Home Office Employer's guide to right to work checks, dated 1 October 2026, and section 48 of the Border Security, Asylum and Immigration Act 2025. It is a practical summary for main contractors, not legal advice.

What changed on 1 October 2026?

Right to work checks used to be a duty owed by an employer to its own employees. Section 48 of the 2025 Act amended the Immigration, Asylum and Nationality Act 2006 in two ways that matter to construction.

First, it widened who counts as an "employer" for the scheme. Engaging someone under a worker's contract, engaging an individual sub-contractor, and running an online matching service now all count, so the business engaging the individual has to check their right to work.

Second, it added a new section 15A, which the guidance calls extended liability. Where a business is under contract to deliver work to a third party and uses another employer's workers to deliver it, liability for illegal working can travel up the chain. The current version of the guidance came into force on 1 October 2026 (Employer's guide, page 12).

Does extended liability apply to main contractors?

Almost certainly, if you deliver projects through subcontractors. The guidance's own first example of an arrangement in scope (Example 7, page 44) is a construction company that wins a contract to build homes and uses a chain of contracts to bring in workers for groundworks and bricklaying. The Home Office says that company may be treated as the employer of any individual who personally carries out work through that chain, and may be liable for a civil penalty if one of them is working illegally.

There are limits. The guidance says extended liability does not apply to every business that buys in work or services, or to a client buying work for its own use (pages 42 to 46). An employment business that only supplies workers to a hirer is also treated differently (Example 12, page 47).

The Home Office also says it will normally look for the person responsible for the relevant contract, rather than treat every party in a chain as liable (page 46). In practice, the question you need to be able to answer is: if an illegal worker were found on our site tomorrow, could we show our arrangements were in place and working?

Who actually carries out the right to work check?

The business with the direct contract with the worker. The guidance is explicit that extended liability does not move the duty to check, and does not make you automatically liable for another employer's failure (page 48).

What it does is give the Home Office a route to you when the direct employer cannot be identified (for example, where a worker cannot say who employs them, or there are several intermediaries) and you have not met the prescribed requirements (page 49). On a construction site with labour-only gangs and second-tier subcontractors, that is a realistic scenario rather than an edge case.

What must a main contractor have in place before work starts?

The guidance sets out three prescribed requirements that establish a statutory excuse (pages 50 to 55). The word that matters most is before. They must be in place before the work or service commences, and you must be able to evidence them if asked.

Requirement	What it means on a construction project	Evidence the Home Office lists
1. Written statement (contract terms)	Your subcontract requires the subcontractor to do prescribed right to work checks; bans further subletting without your written consent (and passes the same duties down if you consent); lets you audit their checks; lets you act if illegal working is found, including suspension or termination; and requires them to co-operate with any Home Office investigation, including details of the whole contract chain.	Copies of agreements and terms, audit records, assurances received, compliance review records, and how concerns were acted on.
2. Substitution controls	Only needed where a contract allows someone to send a substitute. A check must be done on any substitute before they start, the duty cannot be passed to the individual doing the work, and you must be able to confirm the substitute is the person who was checked.	Substitution terms, checks done on substitutes, records of who did the work and when.
3. Identity verification	Proportionate systems so that the person on site is the person whose right to work was checked. The guidance's examples include ID cards or site passes, facial recognition (including certified digital identity providers), biometric or attendance systems, and checks against training records, qualifications or licences for the role.	Evidence of the identity verification measures used.

Two further points from the guidance are worth building into your process:

Re-verification. The Home Office recommends confirming identity again at set intervals, at least once in any 24-hour period or shift (page 54). On a site, the natural point is the daily sign-in at the gate.
Assurances are allowed, blind trust is not. You can rely on assurances from subcontractors that checks have been done, but only if you have taken reasonable steps to satisfy yourself that they are reliable (page 51). The Home Office will look at whether your arrangements actually operated in practice, not only at the contract wording (page 50).

What are the penalties?

According to the guidance (pages 60 and 61):

A civil penalty of up to £60,000 per illegal worker, set case by case.
A criminal offence under section 21 of the 2006 Act where an employer knows or has reasonable cause to believe they are employing an illegal worker, with up to five years' imprisonment and/or an unlimited fine.
Other consequences including business closure and compliance orders, director disqualification, loss of the ability to sponsor migrants, and publication on the government's list of non-compliant employers.

A practical checklist for your next subcontract order

These steps turn the three requirements into something a contracts manager can run on every package. They are our suggested process, drawn from the guidance above.

Update your subcontract terms so they include all five written-statement points from the table: checks, no subletting without consent, audit rights, enforcement and co-operation.
Ask each subcontractor how they check. Before the order is placed, get a short written description of their right to work process and who carries it out.
Name the workforce. Require a list of the individuals who will attend, and update it when the gang changes.
Control substitution. If your subcontract allows substitutes, require notice and a completed check before a substitute arrives.
Verify identity at the gate, every day. Match the person signing in to the named individual, and keep the daily attendance record.
Sample and audit. Ask for evidence of checks for a sample of workers each month and record what you asked for and received.
Act on concerns and record it. If someone refuses to complete a check, or details do not match, suspend access and write down what you did.
Keep the evidence together, so you can produce contracts, assurances, audits and attendance for any worker on any date.

Where DocCompliance fits

DocCompliance does not perform the Home Office check itself. The online share-code check or a certified identity service stays with the employer. What it does is hold the evidence in one place and keep it current:

Right to work documents for every person, whether your own staff or subcontractors' workers, are part of each person's cleared or not cleared status, and only documents a person has reviewed count.
Each subcontractor gets a portal to add their crew and upload documents, and expiry dates are tracked and chased.
A printed site QR code and a per-worker digital badge record who actually came through the gate, day by day, and refuse anyone who is not cleared.
A document-and-attendance pack can be exported for a client, an investigation or an inspector.

If you want to see how this works on your own sites, our guide on how to verify workers on a construction site and our explainer on digital worker badges cover the gate side in more detail.

Frequently asked questions

When did the new right to work rules start?

The extended scheme, including the extended liability rules for contract chains, is covered by Home Office guidance that came into force on 1 October 2026.

Do I have to check the right to work of my subcontractors' workers myself?

The legal duty to carry out the check sits with the business that has the direct contract with the worker. As a main contractor you need the three prescribed requirements in place so that you have a statutory excuse if illegal working is found in your chain.

Can I rely on my subcontractor's word that checks were done?

Yes, but only if you have taken reasonable steps to satisfy yourself that their assurances are reliable. Audits, samples of evidence and a record of how you acted on concerns all help show that.

Does this apply to agency labour?

The guidance treats an employment business that only supplies workers to a hirer differently, and says the extended liability provisions do not apply in that situation. Responsibility stays with the employment business as the employer.

How often should identity be re-checked on site?

The Home Office recommends re-verifying identity at least once in any 24-hour period or shift, proportionate to the risk of substitution or impersonation. For most sites that means at daily sign-in.

What is the maximum civil penalty?

Up to £60,000 per illegal worker. The amount is decided case by case under the Home Office code of practice on preventing illegal working.

Next step

Check your current subcontract template against the five written-statement points above this week. To keep each worker's right to work evidence, expiry dates and daily attendance in one place, you can start a 7-day trial (card required).