CIS tax returns in Mansion House

Construction businesses in Mansion House on either side of the scheme: sole trader and limited company subcontractors with 20% or 30% deductions to reclaim, contractors who pay subcontractors and must file monthly, businesses that do both, and established subcontractors with turnover high enough to apply for gross payment status and stop deductions altogether.

• Subcontractor verification with HMRC and the correct deduction rate (20%, 30% or gross) applied each time
• Monthly CIS300 return filed by the 19th with deduction statements issued to every subcontractor
• Subcontractor annual Self Assessment with CIS deductions reclaimed and the refund chased with HMRC
• Gross payment status application prepared with the turnover, compliance and business tests evidenced
• Domestic reverse charge VAT checked on every CIS invoice in both directions
• CIS deductions offset against PAYE for limited company subcontractors through the EPS each month

1. Tell us your situation

   A short message or call about what you do and what needs filing. We ask the questions that determine the right package and nothing more.

2. Fixed fee in writing

   You receive one price for the work, confirmed by email before anything starts. It does not change if the job takes longer than we expected.

3. Send records, review the draft

   Records come by WhatsApp or email. We prepare the draft, explain the figures in plain English and answer your questions.

4. We file, you get the receipts

   Once you approve and the fee is settled, we submit electronically and forward the HMRC or Companies House acknowledgement the same day.

Mansion House is in Central London, within City of London, in the EC4V postcode district, England. Income tax in England follows the UK rates: 20% basic to £50,270, 40% higher to £125,140 and 45% additional, with the personal allowance of £12,570 tapered away above £100,000. National Insurance, VAT and Corporation Tax are UK-wide, and Stamp Duty Land Tax applies to property purchases.

Confirmation statements and identity verification

Every company must file a confirmation statement at least once a year, within fourteen days of its review date, with a £50 Companies House fee. Since November 2025 directors and people with significant control must also verify their identity with Companies House, and the confirmation statement is where existing officers confirm they have done so during the transition year.

CIS deductions

Under the Construction Industry Scheme, contractors deduct 20% from a registered subcontractor's labour invoices, or 30% if unregistered, and pay it to HMRC. The subcontractor reclaims the deductions against their actual tax through Self Assessment, usually producing a refund because deductions are on turnover while tax is on profit. Contractors file a monthly return by the 19th.

Late filing penalties

HMRC's penalties for a late Self Assessment return are automatic: £100 the day after 31 January, £10 a day from three months late up to £900, then the greater of £300 or 5% of the tax at six and twelve months. Interest and separate late-payment penalties apply to the tax itself. Companies House charges £150 to £1,500 for late accounts, doubling for a second consecutive year.

Making Tax Digital for Income Tax

MTD for Income Tax replaces one annual return with quarterly digital updates and a year-end declaration, submitted from software. The threshold is gross trading and property income, measured two years earlier, and started at £50,000 in April 2026 before falling to £30,000 in April 2027. Anyone affected needs digital record keeping in place before their start date, not after.

The Self Assessment calendar

The tax year runs from 6 April to 5 April. Anyone new to Self Assessment must register by 5 October after the end of the tax year in which their untaxed income began. The online return and the balancing payment are due by 31 January, with a second payment on account on 31 July where they apply. Paper returns have an earlier deadline of 31 October and are rarely sensible.

Payments on account

If your Self Assessment bill exceeds £1,000 and less than 80% of your tax was collected at source, HMRC asks for two advance payments towards the following year, each half of the current bill, due 31 January and 31 July. The first year this happens the January payment is effectively one and a half times the bill. We model it in advance and show you how to reduce the payments if income is falling.

Salary versus dividends

The salary-and-dividend split is the central planning decision for an owner-managed company. Salary costs employer National Insurance above £5,000 but is deductible; dividends are not deductible but attract lower personal rates and no National Insurance. The optimum changes each April with the thresholds and depends on the director's other income, so it should be set deliberately every year.