If you run a limited company, HMRC is changing the way you can submit your tax return from 2026.
On 31 March 2026, HMRC and Companies House will close their joint online filing service which lets small business owners file their annual accounts and company tax returns at the same time.
HMRC and Companies House are closing the service as it no longer ‘meets modern digital standards’. This is because of changes to UK company law and technological updates which the service doesn’t meet.
This is set to affect private limited companies who are required to submit company tax returns. From 1 April 2026, these business owners will need to submit their tax return and accounts using third-party commercial software.
The closure comes at the same time as another big change for limited company owners – with a recent Economic Crime and Corporate Transparency Act update requiring identity verification on Companies House from autumn 2025.
What small business owners need to do next
If you use this service to file your tax return and company accounts, you’ll need to switch to a third-party commercial software before the planned closure. The software you choose will need to work with both Companies House and HMRC, as you’ll no longer be able to submit these at the same time.
While HMRC’s free online filing tool made filing both company accounts and tax returns at the same time possible, the move to third-party commercial software has its benefits. Choosing a commercial software can offer improved validation, tax support, and submission reminders.
Read more: The 8 best self-employed accounting software for 2025
From the next tax year, you’ll need to submit the following to HMRC using third-party software:
- CT600
- CT computation
- company accounts
You’ll also need to continue filing your annual accounts with Companies House.
Download your previous accounts before you lose access
After the service is closed, business owners will be unable to access previous company account filings and tax returns. Because of this, the government is recommending business owners download and save at least three years of accounts.
More guides for limited companies
- HMRC’s crackdown on tax avoidance
- What is Making Tax Digital? A guide for small businesses
- Small business tax changes: new thresholds, rates, and allowances
- When and how to pay corporation tax – a guide for UK businesses
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