Joint Online Filing Service to Permanently Close in 2026
From 1 April 2026, companies will no longer be able to use the joint online service previously provided by HMRC and Companies House to submit their annual accounts and Company Tax returns. The closure marks a significant shift for small and unrepresented businesses, many of whom still rely on this free-to-use service.
Contents
Why Is the Service Being Closed?
HMRC and Companies House are retiring the joint filing service because:
- It no longer meets current digital standards
- It doesn’t support recent changes in UK company law
In their latest guidance, HMRC note that the commercial software market has matured significantly, with many providers now offering enhanced functionality—such as built-in XBRL validation, integrated tax tools, deadline reminders, and full CT600 support.
In essence, the government believes that software providers can now serve the market more effectively.
Submissions from April 2026
From 1 April 2026, most companies must use commercial software to submit their:
- Corporation Tax return (CT600) and supporting computation with HMRC
- Company accounts (via software or paper) with Companies House
You don’t need to inform HMRC or Companies House when you switch. But you do need to be ready in good time—particularly if you're used to handling this yourself without an accountant or software provider.
A paper CT600 can only be filed with HMRC if you have a reasonable excuse or wish to file in Welsh. Companies House will continue to accept paper accounts and web services submissions where permitted.
Downloading Previous Returns
If you’ve filed through the joint service before, you must download and save the last three years of submissions before 31 March 2026.
How to save previous years’ returns:
- Go to the ‘track your submissions’ page and select the period you want to save a copy of your return for.
- Select either the ‘HMRC’ or ‘Companies House’ submission link.
- On the filing summary page, select ‘save your return in HTML’.
- You will be asked where to save the file or it will download to a folder on your computer.
After the service closes on 31 March 2026, companies will no longer be able to access previous returns online. It is important to retain copies of the previous submissions, as you may need these records if:
- You’re subject to an HMRC compliance check
- You want to amend a previously submitted return
- You decide to use an agent to help you in the future, and they ask to see your previous accounts and Company Tax returns
Amendments & Resubmissions
If you need to amend or refile a rejected Corporation Tax return after 31 March 2026, you’ll need to either:
- Use commercial software and re-enter the data
- Submit a paper return to HMRC (if eligible)
- Appoint an agent to handle the submission on your behalf
For Companies House, annual accounts must also be filed using software, web services, or by paper after the joint filing service closes.
CT600 Filing Exemptions
Some companies and organisations that are considered ‘dormant’ for Corporation Tax purposes may be exempt from filing a Company Tax return (CT600) each year. This exemption typically applies to certain charities, community amateur sports clubs (CASCs), and flat management companies, provided they meet HMRC’s qualifying conditions.
However, it’s important to note that even if you don’t need to file a CT600, you must still submit annual accounts to Companies House.
Key Takeaways
- Service Closure Deadline: 31 March 2026 is the final date to use the joint filing service for submissions and to download any previously filed returns.
- Switch to Software: From 1 April 2026, most companies will need to use commercial software to submit their Corporation Tax return (CT600), tax computation, and company accounts.
- No Need to Notify HMRC: You don’t need to inform HMRC or Companies House when you switch to software, but it’s important to plan ahead.
- Past Returns Won’t Be Accessible: Make sure to download and save at least the last three years of filings before the service closes—you may need them for compliance checks or if appointing a new agent.
- Consider Appointing an Agent: If you’re unfamiliar with commercial filing software, XBRL validation or simply want peace of mind, now may be a good time to engage an accountant or tax agent who can manage your filings and ensure compliance from April 2026 onwards.
Get in Touch
The proposed closure of the joint HMRC and Companies House filing service marks a significant change for companies that have relied on this free online solution. With new software requirements on the horizon and just a year until the changes come into effect, early preparation is essential—particularly for businesses that currently manage filings without professional support.
If you'd like guidance on suitable software options, need help downloading your previous submissions, or are considering appointing an agent to manage your filings going forward, contact us today to arrange a free initial consultation.
This article provides general information and should not be considered professional advice. It reflects legislation and practices at the time of writing, which may change. Individual circumstances vary, so please consult us before taking any action. We accept no responsibility for financial loss arising from actions taken without our written advice.
Liam O'Riordan
As Principal at Veritas ATS, I help start-ups, owner-managed businesses, and individuals simplify accounting and tax, providing clear, practical solutions tailored to their needs.
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