The UK construction compliance calendar

Which dates come round every month?

The CIS ones. A CIS tax month runs from the 6th to the 5th, the CIS300 return and the payment and deduction statements are due by the 19th of the month in which it ends, and deductions paid electronically must be cleared in HMRC’s account by the 22nd.

• The return belongs to the month you paid the subcontractor, not the month of the invoice or the work. A payment on the 3rd goes on the previous month’s return.
• A month with no payments is a nil return, due on the same day and carrying the same £100 penalty when it is late.
• Where the 22nd is a weekend or a bank holiday the money has to be there by the last working day before it, and the table above has already moved those dates.

Estimark derives the tax period from the payment date and flags an unsubmitted return past its due date when you look at it. It does not email you on the 18th, and it does not file the return: you file through HMRC’s own service and record the reference.

How do VAT quarters work?

A VAT return and the payment for it are due one calendar month and 7 days after the end of the VAT period, so a quarter ending 30 June is due by 7 August, and the date does not move for a weekend.

• Under the domestic reverse charge the supplier charges no VAT, the net value of the sale goes in box 6 and nothing in box 1, and the customer accounts for the VAT on their own return. The reverse charge has applied since 1 March 2021 and has not changed.
• MTD for Income Tax is a different regime from MTD for VAT. Since April 2026 it has required a quarterly update from the self-employed with income over £50,000, whether or not they are VAT registered, due on 7 August, 7 November, 7 February and 7 May. The threshold falls to £30,000 in April 2027 and £20,000 in April 2028.

Estimark files neither. It stores net, rate and VAT on every invoice, pushes invoices to Xero, QuickBooks or Sage Business Cloud Accounting, and records the SA103 category a quarterly update is built from. The return and the update are prepared and sent from your accounting software.

What renews on a cycle?

Four intervals are fixed by legislation: the landlord gas safety check at 12 months, the EICR for a private rented home in England at 5 years, the thorough examination of lifting equipment at 6 or 12 months, and the scaffold inspection at 7 days. Everything else that renews is a statutory duty with no number in the statute.

• Portable appliance testing has no legal interval. The duty is to maintain equipment so as to prevent danger, and HSE says plainly that an annual test is not required by law. On a construction site HSE’s own guidance has the temporary distribution system inspected and tested every 3 months.
• Fire risk assessments, legionella risk assessments, asbestos reviews and alarm checks are all statutory duties whose instruments name no interval. Estimark’s compliance register defaults to 12, 24, 12 and 12 months and says which intervals are the law’s and which are its own.
• A gas safety check carried out in the two months before the current record expires keeps the original renewal date, so an early check does not drag the anniversary earlier each year.

The compliance register is something you review. Estimark shows what is due and what is overdue when you open it and does not email you before a record falls due.

Which clocks start on an event rather than a date?

Four of them. An F10 notification, a RIDDOR report, an Awaab’s Law hazard and a payment notice each start counting from something that happened, and two of them have a threshold that decides whether they start at all.

• A project is notifiable to HSE on an F10 where the construction work is likely to last longer than 30 working days and have more than 20 workers working simultaneously, or to exceed 500 person days. Either limb triggers it; the first needs both of its conditions.
• A death, a specified injury, a dangerous occurrence or a member of the public taken to hospital is reported to HSE without delay and in writing within 10 days of the accident. An injury that keeps somebody off routine work for more than seven consecutive days is reported within 15 days of the accident, and the fifteen days run from the accident, not from the day it became reportable.
• A social landlord in England investigates a significant damp and mould hazard within 10 working days of becoming aware, gives the tenant a written summary within 3 working days of the investigation ending, and completes the safety work within 5 working days of it ending. An emergency hazard is 24 hours.
• Where a construction contract is silent, the Scheme’s defaults apply: a payment notice within 5 days of the due date, a final date for payment 17 days after it, and a pay less notice no later than 7 days before the final date.

Estimark dates a RIDDOR deadline from the accident and chases it by email every day until the report is recorded as submitted, computes the Awaab’s Law dates in working days, and puts the payment notice dates on the application. It submits nothing to HSE and decides nothing about compliance.

What changes during this tax year?

Three dated events. On 6 October 2026 Scotland’s own damp and mould duties commence, for private landlords as well as social ones. On 30 November 2026 Awaab’s Law Phase 2 commences in England and nine more hazard categories join the statutory clocks. On 6 April 2027 the MTD for Income Tax threshold falls to £30,000.

• Scotland’s clocks are 10 working days to investigate, 3 to give a written summary and 5 to start the repair, counted against Scottish bank holidays, which are not England’s.
• Phase 2 adds excess cold and heat, falls, electrical hazards, fire and explosions, structural collapse and domestic hygiene. A winter heating failure in a social home in England is on a statutory clock from that date.
• Phase 3 has been announced for 2027 and no instrument has been laid.