HMRC's online filing service is closing - here's what you need to know.

From 31 March 2026, HMRC’s free online service to file company tax returns and annual accounts will be permanently closed. This is a significant change for small businesses who have relied on this platform to handle their tax affairs directly.

Here’s a breakdown of what’s changing, what you need to do, and how to prepare for the transition.

Why is the service closing?

The current online filing service no longer meets today’s digital standards or aligns with recent UK company law changes. Since online filing was introduced in 2011, commercial software solutions have evolved dramatically, offering features like:

• Better error-checking and validation

• Built-in tax advice and alerts

• Integration with bookkeeping tools

• Easier submission tracking and reporting

As a result, HMRC is now shifting responsibility for filing onto third-party software providers.

Key dates to remember.

• Up to and including 31 March 2026 - you can still use the HMRC online service to file and amend your company tax return and submit your annual accounts to Companies House.
  

• From 1 April 2026 - You must use commercial software to submit both your company tax return (CT600, computation, and accounts) and your annual accounts.

  
  

What you need to do now...

Start planning ahead.

You don’t need to wait. You can switch to commercial software at any time. HMRC doesn’t require you to notify them when you do. This gives you time to choose the right software that suits your business needs.

Download your past returns.

Before 31 March 2026, make sure you download your previous filed returns. You can do this by logging into your corporation tax account.

If you need to amend a return after the system closes, you can:

• Use commercial software to re-enter and re-submit the return

• File a paper return

• Work with a qualified accountant or tax agent

Can I still file on paper?

Only under specific conditions, such as:

• You have a reasonable excuse (e.g., accessibility needs)

• You want to file in Welsh

  
  

Otherwise, online filing through software is mandatory.

Final thoughts

This shift may feel like a disruption, especially for small businesses used to managing things independently, but with the right software (and support if needed), it can actually streamline your reporting, improve accuracy, and give you more control over your financials.

If you're unsure which software to choose or need help preparing for the switch, our team can guide you through the process. Contact us today for support or a free consultation here.