[ Construction Industry Scheme Specialists ]
CIS Accountants London
The Construction Industry Scheme is one of the most admin-heavy parts of running a building business. We manage CIS end to end — contractor registration, subcontractor verification, monthly returns and the reclaim of any over-deducted tax through self assessment.
Verification
Subcontractor status checked and recorded
Monthly returns
CIS300 filed accurately, every month
Deductions
20% / 30% applied correctly
Reclaims
Over-deducted tax recovered
The Construction Industry Scheme (CIS) requires contractors to deduct tax from subcontractor payments and send it directly to HMRC. The deduction rates are 0% for gross-payment-status subcontractors, 20% for most registered subcontractors, and 30% for anyone unregistered or unverifiable. Getting the rate wrong, forgetting a nil return, or missing the 19th-of-the-month deadline all trigger automatic penalties.
For contractors, we handle the full monthly cycle — verifying every new subcontractor with HMRC before the first payment, calculating the correct deduction on the labour element of each invoice, filing the CIS300 by the 19th of each month, and issuing deduction statements to every subcontractor. For subcontractors, we register you with HMRC, track your deductions throughout the year, and file your self assessment so that any over-deducted tax is refunded to you.
We also help subcontractors build the compliance history needed to qualify for gross payment status (0% deduction rate), which dramatically improves cashflow. And if you have already lost gross status, we can help you get it back by bringing your returns and payments up to date.
[ What We Handle ]
CIS Accountants London — the full scope.
- ◢Contractor CIS registration with HMRC
- ◢Subcontractor verification and status tracking
- ◢Monthly CIS300 returns filed on deadline
- ◢CIS deduction statements for subcontractors
- ◢Reclaiming over-deducted CIS tax via self assessment
- ◢Gross payment status applications and reviews
[ Frequently Asked Questions ]
CIS Accountants London — your questions answered.
What is CIS and who has to register?
CIS is the Construction Industry Scheme — a set of HMRC rules requiring contractors to deduct tax from subcontractor payments and send it to HMRC. Contractors must register with HMRC before taking on subcontractors. Subcontractors must register to avoid being deducted at the highest 30% rate instead of the standard 20%.
When is the CIS monthly return deadline?
The CIS300 monthly return must be filed with HMRC by the 19th of the following month. You must file even if you paid no subcontractors that month — a nil return is still required. Missing the deadline brings automatic penalties that escalate the more returns you miss in a year.
How do I reclaim over-deducted CIS tax?
CIS deductions are advance payments towards your tax bill, not a final tax charge. You reclaim over-deducted tax by filing a self assessment tax return at the end of the tax year — the total CIS deducted is set against your actual income tax and Class 4 NIC liability, and any excess is refunded by HMRC. You need your deduction statements from every contractor to prove what was deducted.
How do I qualify for gross payment status (0% deduction)?
To qualify for gross payment status you must have been in business for at least 12 months, filed all tax returns on time, paid all tax due on time, and have a clean compliance record with no serious tax debts. HMRC reviews these conditions strictly, and a single late return can cause you to lose gross status — so it pays to stay on top of your filings.
What happens if I miss a CIS return?
HMRC issues automatic penalties for late CIS300 returns: £100 immediately, then £200 after six months, plus further penalties after 12 months. Even a nil return filed late attracts the £100 fine. The penalties are per return, so missing several months in a row can quickly add up to thousands of pounds.
Ready to talk to a specialist?
Book a free financial site review and we'll review your CIS, tax and accounts — no obligation.