What is the HMRC Gateway?
By DormantFile · Updated 28 March 2026
The HMRC Government Gateway is an online authentication system that lets you access HMRC's digital services. It is how you (or software acting on your behalf) log in to submit tax returns, including CT600 Corporation Tax returns.
Why you need it
To file a nil CT600 for your dormant company, you need Government Gateway credentials — a user ID and password. These authenticate you with HMRC and prove you are authorised to file on behalf of the company.
HMRC's free CATO filing tool closed on 31 March 2026, so commercial software is now required to submit CT600 returns. We handle nil CT600 filing alongside your dormant accounts — see how it works.
How to get an account
If your company is registered for Corporation Tax, you should already have a Government Gateway account. If not:
- Go to the HMRC online services page on GOV.UK
- Create an organisation account
- Enrol for Corporation Tax using your company's UTR
The process involves identity verification and may take several days.
How we handle your credentials
When you file through DormantFile, your Gateway credentials are used once to authenticate the submission and never stored. We transmit them directly to HMRC at the point of filing. See our security page for details.
Forgotten your credentials?
You can reset your password through the Government Gateway service. If you have lost your user ID, call HMRC on 0300 200 3410.
Read the full guide: How to file a nil CT600 tax return with HMRC