The End of Free Filing.
Why 31st March 2026 is a hard deadline for your company.
If you’ve been running a small or micro-company and DIY-ing your accounts for free, your world is about to change. For over a decade, many directors have used the joint HMRC and Companies House service (often called CATO) to file their accounts and tax returns in one go.
As of 31 March 2026, that service is being switched off for good.
This isn't just a change in website; it’s a total shift in how you’re expected to interact with the taxman. Here is the direct reality of what is happening and what you need to do before the end of the month.
1. No More Web Forms
From 1 April 2026, you will no longer be able to log into the HMRC portal and "type in" your figures. HMRC is exiting the free filing market entirely.
Corporation Tax (CT600): You must now use commercial software to file your tax return.
Companies House Accounts: While Companies House has recently paused their move to "software-only" filing (giving you a bit more time on their specific WebFiling portal), the joint service with HMRC is still ending. This means the days of "filing once for both" for free are over.
2. Download Your History (Or Lose It)
This is the most urgent part. Once the CATO service closes on 31 March, you will lose access to your previous filings. HMRC and Companies House are both recommending that you download and save at least the last three years of accounts and tax returns. If you need to answer an HMRC query or apply for a loan in six months, you won’t be able to just "log in and check" anymore.
3. A New Fixed Cost
Whether you like it or not, compliance is no longer free. You will now need either:
Commercial Software: A subscription to a platform like Xero, QuickBooks, or FreeAgent that includes tax filing.
An Accountant: If you’ve been doing it yourself to save money, it’s time to weigh up whether the software cost and the learning curve are worth the hassle, or if it’s time to pass the baton to a professional.
4. Why the Change?
The official line is that the old system is "outdated" and doesn't meet modern digital standards. It’s also part of the Economic Crime and Corporate Transparency Act, which is designed to make company data more traceable. Essentially, the government wants better data, and they’ve decided that third-party software is the best way to get it.
Your 3-Step Action Plan
Before 31 March: Log into your HMRC/Companies House portal and save every PDF of your past filings. Put them in a secure folder.
Audit Your Software: If you already use accounting software, check if your subscription includes "Tax Filing" (CT600). If it doesn't, you’ll need to upgrade.
Review Your Filing Date: If your company's year-end was Dec 2025, you might be able to squeeze in one last free filing before the 31 March cutoff. Don’t leave it until the 30th—the system will be busy.