TITLE: September Compliance Checklist for UK Limited Companies: Identity Verification, Filing Deadlines, and Software Changes
September is a good time to review your company’s compliance position before the final quarter of the year. For UK Limited Companies, the key priorities this month are director identity verification, software-based filing changes, and keeping Companies House and HMRC deadlines separate.
This guide explains what you need to do and how uk limited company accounting can help you stay organised.
Complete Companies House identity verification before November 2026
Identity verification is now a legal requirement for company directors and people with significant control (PSCs).
If you are an existing director, you must verify your identity during the transition period that began on 18 November 2025. The final transition deadline is in November 2026.
Do not wait until your next filing date. Completing verification early gives you time to resolve any identity or account issues.
Choose your verification route
You can verify your identity in either of two ways:
- Use GOV.UK One Login
- Ask an Authorised Corporate Service Provider (ACSP) to verify you
GOV.UK One Login is free. Depending on your circumstances, you may be asked to verify using an app, online security questions, or a photo ID and Post Office appointment.
An ACSP may be an accountant, solicitor, or another professional supervised under UK anti-money laundering rules. The provider may charge a fee for completing the verification on your behalf.
After successful verification, you receive a unique Companies House personal code. This code belongs to you personally. It does not belong to your company or your employer.
Store and share your personal code securely
You will need your personal code to connect your verified identity with each company role you hold. Directors must provide their codes when filing the company’s next confirmation statement.
Keep the code secure, just as you would protect your HMRC Unique Taxpayer Reference. Share it only with a trusted person or filing provider.
Your September checklist should include:
- Confirm which directors and PSCs still need to verify.
- Complete verification through GOV.UK One Login or an ACSP.
- Save each personal code securely.
- Check the date of your next confirmation statement.
- Give the required codes to the person responsible for filing.
- Confirm that every director has completed the process before the statement is submitted.
Companies House may be unable to accept a confirmation statement unless all current directors have completed the required verification steps. Missing the requirements can also create legal and financial consequences.
Understand the real software filing change
There has been confusion about the filing services that closed in April 2026.
The joint HMRC and Companies House online service for filing accounts and Company Tax Returns closed on 31 March 2026. This is not the same as the standalone Companies House WebFiling service.
As of September 2026:
- Companies House accounts can still be filed using commercial software.
- Eligible accounts can still be filed through Companies House web services.
- Paper filing remains available for now.
- Company Tax Returns must be filed with HMRC using commercial software.
- Companies House WebFiling and paper accounts filing are scheduled to close from 1 April 2028.
- From that date, accounts will need to be filed using commercial software in iXBRL format.
This distinction matters. You do not need to treat April 2026 as the immediate end of all Companies House WebFiling. However, moving to software now is sensible because it gives you time to establish a reliable process before software-only filing becomes mandatory.
Prepare your accounting software now
Choose software that supports both your company accounts and HMRC filing requirements. Confirm that it can:
- Maintain accurate digital accounting records.
- Reconcile bank and payment platform transactions.
- Track inventory and cost of sales.
- Handle foreign currency transactions where required.
- Prepare accounts for Companies House.
- Support the Company Tax Return process.
- Produce the required digital tagging and filing format when applicable.
For ecommerce and digital businesses, this preparation is especially important. Your accounting system may need to bring together Shopify, Amazon, eBay, Stripe, PayPal, payment processors, advertising platforms, payroll, and bank accounts.
Good accounting services for small business UK companies should not simply prepare figures at year-end. They should keep your records updated throughout the year so your statutory filings are based on complete and reconciled information.
Keep the Companies House calendar separate
Companies House deadlines are not the same as HMRC deadlines. Mixing them up can lead to missed filings, late penalties, and unnecessary pressure.
Companies House annual accounts
For most private companies, annual accounts must be delivered within 9 months of the accounting reference date (ARD).
Your ARD is normally the company’s financial year-end. The deadline is calculated to the exact day. Companies House must receive acceptable accounts by the deadline. Sending them on the due date may not be enough if they are rejected or received late.
For example:
- Accounting reference date: 30 September 2026
- Companies House accounts deadline: 30 June 2027
Late filing penalties for a private company can start at £150 and increase depending on how late the accounts are filed.
Companies House confirmation statement
A confirmation statement keeps the public register up to date. You must file at least one confirmation statement during every 12-month review period.
You normally have 14 days after the end of the review period to file it.
The confirmation statement may need to confirm details such as:
- Registered office address.
- Directors and secretary.
- People with significant control.
- Share structure.
- Shareholders.
- Principal business activities.
- Director identity verification information and personal codes.
A confirmation statement is required even if nothing has changed. Filing it on time helps keep your company record accurate and supports banking, funding, marketplace, and supplier checks.
Keep the HMRC calendar separate
HMRC uses a different timetable for Corporation Tax.
Corporation Tax payment
Corporation Tax is usually due 9 months and 1 day after the end of the accounting period.
For a company with a 30 September 2026 accounting period end, the payment deadline is usually:
- Corporation Tax payment deadline: 1 July 2027
You should calculate and reserve funds for the tax payment before the deadline. Waiting until the CT600 filing date can create a cash-flow problem because payment is normally due earlier.
Company Tax Return and CT600
The Company Tax Return, commonly filed using form CT600, is normally due 12 months after the end of the accounting period.
For the same company:
- Accounting period end: 30 September 2026
- Corporation Tax payment deadline: 1 July 2027
- CT600 filing deadline: 30 September 2027
