UK What Is CIS

The Construction Industry Scheme catches more businesses than most owners expect. If you pay subcontractors more than £1,000 in a month, you’re likely a CIS contractor with monthly filing obligations.

Get it wrong and HMRC’s automatic penalties start at £100, rising to £3,000 per month.

The real burden arrives at month-end when your bookkeeper races to verify three new subcontractors while you’re chasing invoices.

Many construction businesses now face both CIS deductions and VAT reverse charge requirements on the same transactions, creating a compliance burden that can absorb several hours each month just to process payments correctly.

What is the Construction Industry Scheme?

CIS is HMRC’s system for collecting tax and National Insurance from construction workers before they’re paid.

In our assessment of how CIS is understood by businesses entering the construction supply chain for the first time, we find the gross/standard/higher deduction rate structure is rarely explained clearly by the agencies or contractors who trigger the registration obligation.

Instead of subcontractors handling their own tax through self-assessment, contractors deduct 20% or 30% from each payment and send it directly to HMRC.

The scheme applies to most construction work: building, decorating, repair, demolition, and site preparation, as set out in HMRC's guidance on the Construction Industry Scheme (CIS).

If you regularly use subcontractors for any of these activities, you’re likely caught regardless of your main trade.

You become a CIS contractor if your construction payments to subcontractors exceed £1,000 in any calendar month.

This includes labour-only payments, materials supplied by the subcontractor, and VAT where you’re not registered for reverse charge.

The £1,000 threshold is cumulative across all subcontractors. Three payments of £350 each would trigger CIS obligations for that month and require you to register as a contractor within 30 days.

How does the Construction Industry Scheme work?

As a contractor, you must verify each subcontractor with HMRC before making any payment. This tells you their CIS status and the correct deduction rate to apply.

We find the verification step before first payment is the most frequently skipped part of the process, creating a default to the higher 30% rate that is then difficult to unwind once payments have been made.

Picture Friday afternoon. Your plasterer finished on Wednesday, needs payment today, and HMRC’s verification system shows “technical difficulties”.

Subcontractors fall into three categories: those not registered (30% deduction), those registered for CIS (20% deduction), and those with gross payment status (0% deduction).

The verification process happens through HMRC’s online system. You enter the subcontractor’s name, National Insurance number or UTR, and postcode, and the system responds with their status and the deduction rate to apply.

For each payment, you deduct the specified percentage from the labour element only.

Materials supplied by the contractor are not subject to CIS deductions, but materials supplied by the subcontractor are included in the deduction calculation.

Monthly returns must be filed by the 19th of the following month. Late filing triggers automatic penalties regardless of whether any payments were made.

Even months with zero construction payments require a nil return, a requirement that catches businesses every December.

Gross payment status qualification

Gross payment status lets subcontractors receive full payments without deductions, but qualification is restrictive.

You must demonstrate business compliance, financial stability, and that construction work is your main activity.

The key tests include: annual construction turnover of at least £30,000, a dedicated business bank account, up-to-date tax and VAT obligations, and appropriate insurance.

Your business must have been trading for at least 12 months with construction as the primary activity.

Only 23% of first-time applications succeed. The most common failures are inadequate business bank account arrangements and insufficient evidence of construction turnover.

HMRC requires three years of accounts or certified turnover figures from an accountant.

Why does the Construction Industry Scheme matter for your business?

CIS creates cash flow and administrative burdens that many business owners underestimate.

In our review of CIS compliance failures, we find the operational burden falls disproportionately on subcontractors who have not registered for gross payment status: the monthly deductions create cashflow pressure that forces some businesses to borrow against receivables they are already owed.

The monthly filing obligation continues whether you make construction payments or not, and the penalties for non-compliance are automatic.

Watch your finance director’s face when you explain that the £600 penalty for missed returns during your summer holiday is non-negotiable.

If you’re used to annual self-assessment or quarterly VAT returns, the monthly CIS cycle is a significant increase in compliance work.

Each return takes 15-30 minutes for simple cases, longer where verification issues arise.

The scheme also affects your payment timing. You cannot pay subcontractors until HMRC confirms their verification status.

During peak periods (month-end, quarter-end), verification delays of 2-5 working days are common, potentially disrupting your payment schedules.

Cost of non-compliance

CIS penalties escalate quickly and compound with interest. A business that misses three consecutive monthly returns faces £600 in penalties before interest, rising to £3,000 monthly for continued non-compliance.

Beyond financial penalties, failure to operate CIS correctly can trigger deeper HMRC investigations into your business structure and employment practices.

If HMRC determines you’ve misclassified employees as subcontractors, you face retrospective PAYE and National Insurance liabilities.

The verification requirement also creates operational risks.

Pay a subcontractor without proper verification and you remain liable for the tax that should have been deducted, even if the subcontractor subsequently pays their own tax.

What are the alternatives to Construction Industry Scheme compliance?

For most construction businesses, there is no alternative to CIS compliance once you cross the £1,000 monthly threshold. However, you can structure your operations to minimise the administrative burden.

In our assessment of the available routes, we find the practical question is not whether to comply with CIS but how to structure the administration so it does not consume disproportionate payroll and finance resource.

Some businesses consolidate subcontractor payments to reduce the frequency of verification checks.

Instead of multiple small payments, you might pay weekly or fortnightly, reducing the number of separate CIS calculations required.

Alternatively, you could work with subcontractors who have gross payment status, eliminating the deduction calculation entirely.

However, this limits your contractor pool since only 15-20% of construction subcontractors achieve gross payment status.

For businesses just above the £1,000 threshold, restructuring payment arrangements might reduce your exposure.

If subcontractors provide their own materials and invoice separately for materials and labour, only the labour element counts toward the CIS threshold.

Another approach is using employment rather than subcontractor arrangements for regular workers.

PAYE obligations are often simpler than monthly CIS compliance, especially for businesses with consistent workforce requirements.

Your accountant will prefer PAYE. Your workers might not.

CIS FAQs

Do I need to register for CIS if I only occasionally use subcontractors?

Yes, if your payments to construction subcontractors exceed £1,000 in any calendar month. The threshold is cumulative across all subcontractors and includes labour, materials supplied by the subcontractor, and VAT. Even occasional use can trigger registration requirements if payments cluster in a single month, so check the running monthly total before each payment run rather than waiting for an annual review.

What happens if I pay a subcontractor before verifying their CIS status?

You become liable for the tax that should have been deducted, even if the subcontractor later pays their own tax. HMRC can pursue you for the full deduction amount plus penalties and interest.

The default rate for unverified subcontractors is 30%, so an unverified payment also costs the subcontractor 10 percentage points more than a verified one. Always verify before payment.

Can I apply both CIS deductions and VAT reverse charge to the same payment?

Yes, for construction services over £250 where both rules apply. Apply CIS deductions to the labour element and reverse charge to the VAT element.

You will need to account for both on separate HMRC returns, so the subcontractor invoice must show labour, materials, and VAT separately. Most construction payroll software handles the split automatically once you flag the supplier as both CIS and reverse-charge in scope.

How long does CIS verification take?

Usually instant through HMRC's online system, but delays of 2-5 working days occur during peak periods such as month-end and quarter-end. Plan payment runs to avoid these bottlenecks by verifying new subcontractors at onboarding rather than the day before payment. Verification results stay valid for the current and following two tax years, so once a subcontractor is on file you rarely need to re-verify mid-engagement.

What records must I keep for CIS compliance?

Verification records for each subcontractor, monthly payment summaries showing gross amounts and deductions, copies of monthly returns submitted to HMRC alongside RTI payroll filings, and payment vouchers showing net amounts paid. Keep all records for at least three years after the end of the tax year. HMRC compliance checks often request several years of records in one go, so a structured digital archive saves days of retrieval work when an inspection lands.

Methodology and disclosure

This article is based on current HMRC guidance, enforcement statistics from FOI requests, and surveys from professional bodies including CIOT and ICAEW.

We reviewed penalty data from HMRC’s 2023-24 compliance statistics and processing times from user reports across construction industry forums.

Whichapp provides payroll software comparison and guidance for UK businesses. We do not provide tax advice and recommend consulting with qualified professionals for complex CIS situations.

See our construction payroll guide for related compliance requirements.

We did not directly test HMRC’s verification system response times or review individual penalty case files. Enforcement statistics are based on published aggregate data rather than specific case analysis.