The End of Free Tax Filing: What UK Business Owners Must Do Before 31 March 2026

The End of Free Tax Filing: What UK Business Owners Must Do Before 31 March 2026

If you manage your own company’s finances, big changes are coming to your April to-do list. Companies House and HMRC have announced they are permanently closing their joint online filing service on 31 March 2026.

This means the free, integrated option for filing your company tax returns and annual accounts is vanishing. Going forward, most businesses will be legally required to transition to commercial software.

Critically, when the system shuts down, all historical records held within it will be permanently deleted.

Here is what you need to know about the shutdown, why it's happening, and the urgent steps you must take to protect your company's data.

🚨 Urgent: Download Your 3-Year History Now

Because the joint filing service is being completely retired, the financial information you previously filed will not be archived or transferred. If you don't download it yourself, it will be lost forever.

Companies House strongly recommends downloading and saving at least three years of accounts filings as a matter of urgency.

How to back up your data:

1.       Log into your HMRC online service.

2.       Head over to the "Track your submissions" page.

3.       Select the period of the return you need.

4.       Save the file directly to your computer in HTML format.

*Note: If you need to amend a previous return or re-file a rejected one after 1 April, you will have to manually re-enter all of this financial information into commercial software from scratch. Having these downloads handy will save you hours of administrative headaches.*

🔄 What Changes on 1 April 2026?

Starting 1 April 2026, the process splits depending on whether you are submitting to HMRC or Companies House.

1. Company Tax Returns (HMRC)

The old, free HMRC online portal is gone. You must use commercial third-party software to file your Company Tax Return (CT600).

·         The Exceptions: Paper returns will only be accepted under highly restrictive circumstances, such as companies wishing to file in Welsh or those who can provide HMRC with a strictly defined "reasonable excuse."

2. Annual Accounts (Companies House)

While the joint service is ending, Companies House is maintaining a few more options for submitting your annual accounts. You can use:

·         Commercial third-party software.

·         The standalone Companies House Web Filing service.

·         Traditional paper filing by post.

At a Glance: Old vs. New System

Why is the System Closing?

According to Companies House, the joint system is outdated and no longer aligns with modern digital standards. The closure is part of a broader push to upgrade security, accommodate enhanced corporation tax requirements, and support changes under the Economic Crime and Corporate Transparency Act to prevent financial crime.

The transition also follows a recent IT security breach in March 2026. The vulnerability was linked to the government's rollout of the new Gov.uk One Login system, which is replacing the old Government Gateway. While authorities emphasize that the breach has been fully resolved and secured, it has accelerated the government's push toward a fully digitalized, software-driven filing ecosystem that aligns with international best practices.

Next Steps for Business Owners

If you usually file your own returns using the free government tool, your immediate priority today should be logging in and securing your historical HTML files.

Next, you'll need to research and invest in HMRC compatible commercial accounting software before your next tax deadline. If you work with an accountant, reach out to them this week to ensure your business is transitioned and ready for the April cutoff.