HMRC is closing its free Company Tax Return filing service – what your business needs to do now

From 31 March 2026, HM Revenue & Customs (HMRC) will permanently close its free online service for filing Company Tax Returns and annual accounts.  

If you currently rely on this system, you will need to switch to commercial software to stay compliant. 

Why is HMRC closing its free Company Tax Return system? 

HMRC says the platform no longer meets current digital standards or reflects recent changes in UK company law.  

The system was designed over a decade ago for small, unrepresented companies with simple tax affairs. 

Today, specialist tax software offers a wider range of features, including: 

• Better validation checks 

• Integrated support and reminders 

• Seamless filing to both HMRC and Companies House 

How to prepare for the HMRC filing service closure 

You do not need to wait until the last minute to make the switch. Start planning now by: 

• Reviewing your current process, especially if you are still using HMRC’s portal 

• Choosing commercial software that lets you file CT600s, tax computations and company accounts 

• Setting up your new software and running tests ahead of your next filing deadline 

There is no need to notify HMRC or Companies House when you move to commercial software. 

Download past Company Tax Returns before they are deleted 

After 31 March 2026, you won’t be able to access your previously filed returns through HMRC’s service.  

It is important to download and save at least the last three years of submissions, in case you: 

• Need to refer back during a compliance check 

• Hire an accountant or agent who needs your past filings 

• Want to resolve queries with HMRC or Companies House 

To download a return: 

1. Log in to HMRC and go to ‘track your submissions’ 

1. Choose the filing period and select the HMRC or Companies House link 

1. On the summary page, click ‘save your return in HTML’ 

1. Save the file to your computer or a secure folder 

How to amend or refile Company Tax Returns after 31 March 2026 

Once the HMRC service closes, you won’t be able to amend or resubmit returns through the portal. Instead, you must: 

• Use commercial filing software (you will need to re-enter the information) 

• File by post to the Corporation Tax office 

• Ask a tax adviser or accountant to file on your behalf 

Companies House will also only accept changes via software or paper submission. 

Do dormant companies still need to file accounts? 

Yes, even if your company is dormant and not trading, you must still file accounts with Companies House each year.  

Some dormant entities may qualify for a Corporation Tax exemption, such as: 

• Charities 

• Flat management companies 

• Community amateur sports clubs 

Even if exempt from Corporation Tax, you must still keep Companies House updated annually. 

Don’t wait until the deadline to switch software 

With the closure of HMRC’s filing system looming, many businesses will be moving to new platforms over the coming year.  

This could lead to longer wait times for support, limited availability of training, and a greater risk of errors. 

By switching early, you will avoid the rush and get familiar with your new system. 

Need help preparing for the change? 

We can help you choose the right software, transfer your data securely, and keep your tax filings on track.  

Contact us today to speak to one of our tax and accounts specialists.