The Construction Industry Scheme (CIS) affects how many construction businesses pay subcontractors and report those payments to HMRC. Contractors need to check who falls within the scheme, verify subcontractors, apply the correct deductions, and submit returns on time. Clear records make these tasks easier and help explain how each payment was calculated. The rules can depend on the work and the parties involved, so treat this as a practical overview and check current HMRC guidance for your circumstances.
Check whether CIS applies
CIS generally covers payments made by contractors to subcontractors for construction work. A business may count as a contractor if it pays subcontractors to carry out construction operations, or if construction spending forms a significant part of its business. Some businesses that do not ordinarily work in construction may still have CIS obligations. Check the nature of the work, who is paying, and whether any exemptions apply before deciding how to handle a payment.
Not every service connected with a building project is treated the same way. CIS covers specified construction operations, while some activities may fall outside the scheme or qualify for an exception. Review the actual work described in the agreement and invoice rather than relying only on a job title or supplier category. When the status is uncertain, check HMRC guidance or seek qualified advice before paying.
Verify subcontractors and deductions
Before making a CIS payment, contractors generally need to verify subcontractors with HMRC, unless the subcontractor has already been verified under the applicable rules. Verification helps establish the deduction rate to use. Keep the verification outcome with the subcontractor’s file, along with their legal or trading name, business details, Unique Taxpayer Reference where applicable, and the date the check was completed.
CIS deductions apply to the relevant payment for construction work, not automatically to every amount on an invoice. Materials and certain other costs may be treated differently when they are properly identified and supported. Check the invoice breakdown and the rules for allowable deductions, then calculate the amount withheld using the subcontractor’s verified status. Give the subcontractor a payment and deduction statement showing the payment details and CIS deduction.
File returns and pay HMRC
Contractors usually need to send a CIS monthly return to HMRC for each tax month in which they pay subcontractors. The return reports payments and deductions, and contractors must also meet their obligations when no relevant payments were made, where required. Track the tax-month deadline in your accounts calendar and allow time to review the figures before submission. Late or inaccurate returns can lead to penalties and additional administration.
Keep a record of the return submitted, any confirmation from HMRC, and the amount and date of each CIS payment made to HMRC. Reconcile those figures against your bookkeeping records and bank transactions. If a subcontractor’s details or payment changes after filing, follow HMRC’s process for correcting the return rather than leaving the difference unexplained. Assign a named team member to monitor submissions and resolve queries.
Build a dependable CIS paper trail
Maintain a separate, organized record for each subcontractor. Useful documents include contracts or work orders, invoices, verification results, payment calculations, deduction statements, and correspondence about changes to the work or payment. Keep copies of monthly returns and evidence of payments to HMRC as well. Consistent naming and filing make it easier to answer questions, prepare accounts, and identify missing information before a deadline.
Record the gross amount paid, the value and evidence for materials where relevant, the amount subject to deduction, the deduction rate, and the net payment. Reconcile these details regularly rather than waiting until year-end. Set a retention process that follows current HMRC requirements, and restrict access to sensitive supplier and tax information. If you use accounting software, check that its CIS settings and reports reflect your actual payment process.
CIS administration works best as a routine: confirm the scheme applies, verify subcontractors, calculate and report deductions, and keep supporting records together. Review your process whenever your work or subcontractor arrangements change, and check current HMRC guidance for specific rules. SiteLedger Accounting can help construction businesses in Nottingham review their CIS bookkeeping and reporting process.